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Diseases » Learning disabilities » Glossary
 

Glossary for Learning disabilities

  • 2-Methylbutyric Aciduria: A very rare genetic disorder where an enzyme deficiency prevents the break down of certain proteins into energy and results in a harmful accumulation of acids in the blood and body tissues. More specifically, there is a deficiency of an enzyme (2-methylbutyryl-coenzyme A dehydrogenase) needed to convert the amino acid isoleucine into energy. 2-methylbutyrylglycine levels build up in the body and may cause damage. Symptoms vary according to the degree of enzyme deficiency - can range from asymptomatic to life-threatening.
  • 2-methylbutyryl-coenzyme A dehydrogenase deficiency: A very rare genetic disorder where an enzyme deficiency prevents the break down of certain proteins into energy and results in a harmful accumulation of acids in the blood and body tissues. More specifically, there is a deficiency of an enzyme (2-methylbutyryl-coenzyme A dehydrogenase) needed to convert the amino acid isoleucine into energy. 2-methylbutyrylglycine levels build up in the body and may cause damage. Symptoms vary according to the degree of enzyme deficiency - can range from asymptomatic to life-threatening.
  • 22q11.2 deletion syndrome: A rare genetic disorder caused by the absence of a small portion of genetic material. A small section of chromosome 22 is missing at a location called q11.2. Chromosome 22 is one of 23 pairs of chromosomes that exist in humans.
  • 3-methylglutaconic aciduria, type 1: A recessively inherited metabolic disorder characterized by methylglutaconic acid in the urine.
  • 3-methylglutaconic aciduria, type 4: A rare genetic disorder where the body's cells are unable to make sufficient energy resulting in an accumulation in the body of 3-methylglutaconic acid. Type 4 is characterized by symptoms which overlap type 1 and 3.
  • 47 XYY syndrome: A genetic condition where males have an extra Y chromosome in each of their cells. Normally male cells have one X and one Y chromosome. This is not usually an inherited condition but a defect that occurs during cell division. Often the condition is asymptomatic.
  • 47,XXX syndrome: A genetic condition where females have an extra X chromosome in each of their cells. Normally female cells have two X chromosomes. This is not usually an inherited condition but a defect that occurs during cell division. Often the condition is asymptomatic.
  • 49,XXXXX syndrome: A rare chromosomal disorder that affects only females and involves body cells having five copies of the X chromosome instead of the normal two.
  • 6-pyruvoyl-tetrahydropterin synthase deficiency: A rare genetic disorder where insufficient levels of tetrahydropterin leads to a build up of phenylalanine in the blood which can cause toxic side effects such as nerve damage or even brain damage. The condition does not usually cause any significant symptoms.
  • ADD: Attention Deficit Disorder (ADD) is a mental and behavioral disorder characterized by behavioral problems such as hyperactivity, inattention, concentration difficulty, and other mental symptoms. The related description Attention Deficit Hyperactivity Disorder (ADHD) may be a more modern description of the disease.

    Misdiagnosis of ADD is a well-known controversy in the sense that cases of hyperactivity in children may be over-diagnosed. There is a tendency for parents to seek and doctors to prescribe the drug Ritalin even in cases where the diagnosis of ADD or ADHD may be incorrect. Alternative diagnoses include normal child behavior (i.e. just an active child), food intolerances, or other behavioral disorders (see misdiagnosis of ADD).

    On the other hand, ADD is under-diagnosed in adults, with a large number of adults having ADD without knowing it; see misdiagnosis of Adult ADD.

  • ADHD: Attention Deficit Hyperactivity Disorder (ADHD) is a mental and behavioral disorder characterized by behavioral problems such as hyperactivity, inattention, concentration difficulty, and other mental symptoms. Typically, ADHD and associated hyperactivity is known as a childhood disorder, although ADD/ADHD in adults is known to be under-diagnosed. It is distinguished from Attention Deficit Disorder (ADD) which has a reduced focus on hyperactivity type symptoms.
  • Absence of septum pellucidum and septo-optic dysplasia: A rare birth defect where a thin membrane in the middle of the brain is missing. This brain abnormality is never present on it's own but is a characteristic of septo-optic dysplasia where the patient also has optic disk abnormalities and pituitary deficiencies.
  • Adenylosuccinate lyase deficiency: A rare inherited disorder characterized by a deficiency of the enzyme called adenlyosuccinate lyase which generally results in psychomotor retardation and autistic behavior.
  • Adult ADHD: Adult ADHD, (attention deficit hyperactivity disorder) is a common neurobehavioral developmental disorder with an onset in childhood that continues into adulthood. Children do not simply grow out of ADHD, as is often believed. Just the opposite is commonly true - the symptoms of ADHD often get worse as a child grows into adulthood. The predominant behaviors of adult ADHD are the same as in children and include:
    • Inattentiveness
    • Hyperactivity
    • Impulsivity

    These behaviors result in difficulties with:

    • Concentration
    • Remaining focused on a task or activity
    • Controlling behavior
    • Hyperactivity or over-activity

    The symptoms of adult ADHD can be treated, but there currently is no cure for the disorder. Most people with ADHD can be successfully treated and lead normal, productive lives at home, work, school and with friends and family. The cause or causes of ADHD are not yet known, although researchers believe that genes may be one factor in the development of the disease. It is most likely that the disorder is the result of a combination of elements, including environmental factors, traumatic head injuries, nutrition, and social influences.

  • Aicardi-Goutieres syndrome: A rare inherited progressive disease that affects the brain and immune system.
  • Akesson syndrome: A very rare syndrome characterized by excessive skin folds and furrows on the scalp, mental retardation the failure of the thyroid to develop.
  • Allan-Herndon-Dudley Syndrome: A very rare inherited disorder characterized primarilty by mental retardation.
  • Amelo-cerebro-hypohidrotic syndrome: A rare syndrome involving degeneration of the central nervous system, seizures and abnormal tooth development.
  • Apert syndrome: A rare condition characterized by abnormalities in the appearance of the face and head as well as finger and toe abnormalities. The bones of the skull fuse together too early which prevents it from growing normally. Various toes and fingers may be fused together.
  • Arginase deficiency: A very rare urea cycle disorder caused by a deficiency of the enzyme (arginase) needed to convert ammonia to the urea which can then be removed in the urine. The condition leads to excess build-up of ammonia in the body which is toxic to the nervous system.
  • Arterial occlusive disease, progressive -- hypertension -- heart defects -- bone fragility -- brachysyndactyly: A rare syndrome characterized by narrowing or blockage of a number of arteries (in the kidneys, abdomen, brain and heart) as well as fragile bones, heart defects and finger abnormalities. Fractures and high blood pressure often start during the first years of life.
  • Aspartylglucosaminuria: A rare glycoprotein metabolism disorder caused by a deficiency of an enzyme called aspartylglucosaminidase. Patients tend to develop normally during the first few years of life and development continues slowly until adolescence when mental retardation becomes progressively worse.
  • Athabaskan brainstem dysgenesis: A rare neurological disorder caused by abnormal brainstem development and function.
  • Attention Deficit Hyperactivity Disorder: Behavioral disorder with hyperactivity and/or inattention.
  • Auditory Processing Disorder: Failure of the brain to correctly process sound.
  • Autism: Childhood mental condition with social and communication difficulties.
  • Baller-Gerold Syndrome: A rare syndrome characterized by premature fusion of skull bones and radial defects. Variable other abnormalities may be present.
  • Baraitser-Winter syndrome: A rare syndrome characterized by a structural eye defect, droopy eyelids and mental retardation.
  • Bardet-Biedl Syndrome: A rare genetic disorder characterized by mental retardation, obesity, polydactyly and retinal pigmentation as well as other abnormalities.
  • Behr syndrome: A rare inherited neurological condition characterized by spastic paraplegia and sometimes optic atrophy.
  • Borjeson-Forssman-Lehmann Syndrome: A rare genetic disorder characterized by severe mental deficiency, large ears, hypogonadism and other abnormalities.
  • Branchial arch syndrome X-linked: A rare syndrome characterized by a range of abnormalities such as facial anomalies, impaired hearing, short stature, learning disability and branchial arch defects.
  • Bronchopulmonary dysplasia: A rare form of infant lung disease that usually occurs as a complication of ventilator use in premature babies.
  • CAMFAK syndrome: A rare syndrome characterized by cataracts, small head, failure to thrive and spinal curvature.
  • CHARGE Syndrome: A rare disorder characterized by choanal atresia, coloboma, ear and genital abnormalities and congenital heart defects.
  • Cardiofaciocutaneous Syndrome: A rare genetic disorder characterized by short stature, congenital heart defects skin anomalies and frontal bossing.
  • Cerebral palsy, spastic, diplegic: Brain damage that involves muscle rigidity that occurs either in both arms or in both legs. The brain damage is often the result of a birth defect or some sort of trauma to the brain.
  • Cerebrocostomandibular Syndrome: A rare genetic disorder characterized by a very small jaw, abnormal rib development and a small thorax as well as other abnormalities.
  • Ceroid lipofuscinosis, neuronal 1, infantile: A rare inherited biochemical disorder involving the progressive accumulation of certain chemicals (lipopigments) in body tissues due to deficiency of an enzyme (palmitoyl-protein thioesterase) needed to process it.
  • Ceroid lipofuscinosis, neuronal 3, Juvenile: A progressive genetic disorder where defective lipid metabolism that causes blindness, neurological deterioration, dementia leading to total incapication within years and death within 10-15 years.
  • Ceroid lipofuscinosis, neuronal 5: A rare metabolic disorder that affects the nerve cells of the body and is characterized by the deposits of lipopigments (lipofuscin). Type 5 is distinguished from other types by the origin of the genetic defect.
  • Child abuse: Physical, sexual, emotional abuse or neglect of child.
  • Child health conditions: Any medical conditions typically afflicting children.
  • Childhood disintegrative disorder: A rare disorder where a period of normal development (a couple of years) is followed by delays in the development of motor, social and language skills. Previously acquired skills are lost.
  • Chromosome 12p tetrasomy syndrome: A rare chromosomal disorder where there are four copies of the short arm (p) of chromosome 12 rather than the normal two resulting in various abnormalities.
  • Chromosome 13 trisomy syndrome: A rare chromosomal disorder where there are three copies of chromosome 13 rather than the normal two resulting in various abnormalities. Most die within months and there are few survivors after 10 years.
  • Chromosome 1q21.1 Duplication Syndrome: A rare chromosomal disorder caused by the duplication of a portion of chromosome 1 at a specific location (1q21.1). The main symptoms were autism and mental retardation as well as other physical anomalies.
  • Chromosome 22, microdeletion 22q11: A rare chromosomal disorder where a portion of the long arm of chromosome 22 is deleted.
  • Chromosome 22q deletion: A rare genetic disorder where a portion of the genetic material from the long arm of chromosome 22 is missing. The symptoms or severity may vary somewhat between patients.
  • Chromosome 22q11 Deletion Spectrum: A rare chromosomal disorder where a small piece of genetic material is missing from chromosome 22 at the q11 location.
  • Chromosome 22q11.2 deletion syndrome: A rare genetic disorder caused by the absence of a small portion of genetic material. A small section of chromosome 22 is missing at a location called q11.2. Chromosome 22 is one of 23 pairs of chromosomes that exist in humans.
  • Chromosome 22q11.2 microduplication: A rare chromosomal disorder where a part of the chromosome 22 genetic material at the q11.2 location is duplicated resulting in various anomalies ranging from mild to severe amongst different patients.
  • Chromosome 4 ring syndrome: A rare chromosomal disorder where the ends of chromosome 4 have been deleted and the two broken ends have rejoined to form a ring shape resulting in a range of symptoms determined by the size and location of the genetic deletion.
  • Chromosome 6 ring syndrome: A rare chromosomal disorder where the ends of chromosome 6 have been deleted and the two broken ends have rejoined to form a ring shape resulting in a range of symptoms determined by the size of the genetic deletion.
  • Chromosome 7 deletion p21-p22.1: A chromosomal disorder where a small portion of chromosome 7 is deleted which results in a range of abnormalities.
  • Chromosome 8 recombinant syndrome: A rare recombinant chromosomal disorder involving chromosome 8 which results in various abnormalities.
  • Chromosome 8 trisomy syndrome: A rare chromosomal disorder where there are three copies of chromosome 8 rather than the normal two which results in various abnormalities.
  • Chromosome 8, mosaic trisomy: A very rare chromosomal disorder where there is an extra copy of chromosome 8 in some of the body's cells. Some cases with this chromosomal abnormality have no clinical symptoms. The presence of abnormalities in some cases is dependent on which body cells contain the chromosomal defect.
  • Chromosome 8, trisomy: A rare chromosomal disorder where there are three copies of chromosome 8 rather than the normal two which results in various abnormalities. The type and severity of symptoms varies depending on the amount and exact location of the genetic material that is duplicated.
  • Chromosome 9 inversion or duplication: A very rare genetic disorder where a portion of chromosome 9 is inverted or duplicated which results in various abnormalities. The type and severity of symptoms varies depending on the size and location of the genetic material involved.
  • Chromosome 9 trisomy syndrome: A rare chromosomal disorder where there are three copies of chromosome 9 in the body's cells instead of the normal two resulting in various abnormalities.
  • Chromosome 9, partial trisomy 9p: A very rare genetic disorder where a portion of the genetic material on the short arm (p) of chromosome 9 is duplicated which results in various abnormalities. The type and severity of symptoms varies depending on the size and location of the genetic material involved.
  • Chylomicron Retention Disease: A rare condition characterized by the inability of the intestines to absorb fats from the diet which cause failure to thrive in infants.
  • Classic childhood ALD: Classic severe form of ALD in boys.
  • Cockayne syndrome: A rare genetic disorder characterized by a senile-like appearance, hearing and vision impairment and sun sensitive skin.
  • Coenzyme Q 10 (CoQ10), deficiency: A rare inherited disorder characterized by the deficiency of Coenzyme Q 10. The range and severity of symptoms is variable.
  • Coffin syndrome 1: A rare inherited syndrome characterized mainly by spasticity, seizures, congenital heart defects, short stature and delayed mental and motor development.
  • Coffin-Lowry syndrome: A rare genetic disorder characterized by down slanting space between eyelids, bulbous nose, soft hands and tapering fingers.
  • Coffin-Siris Syndrome: A rare genetic disorder characterized by underdeveloped or absent fifth finger and toenails and coarse facial features.
  • Cohen Syndrome: A rare genetic disorder characterized by reduced muscle tone, obesity and prominent front teeth.
  • Coloboma uveal with cleft lip palate and mental retardation: A very rare syndrome characterized by a cleft lip and palate, mental retardation and a gap or hole in the iris or uvea of the eye (iris or uveal coloboma).
  • Coloboma, cleft lip/palate and mental retardation syndrome: A very rare syndrome characterized by a cleft lip and palate, mental retardation and a gap or hole in the iris or uvea of the eye (iris or uveal coloboma).
  • Communication disorders: Various disorders limiting the ability to communicate (including developmental communication disorders)
  • Congenital disorder of glycosylation type 2A: A very rare inherited metabolic disorder where defective carbohydrate compounds are attached to glycoproteins and thus impairing glycoprotein function. Type 2A has a GlcNAc transferase 2 enzyme defect.
  • Congenital myotonic dystrophy: A form of muscular dystrophy which is usually apparent at birth or within a few years. and affects the skeletal muscles, heart conduction, smooth muscle, eyes and the central nervous system. The range of severity varies from asymptomatic to fetal death.
  • Cornelia de Lange Syndrome: A very rare disorder involving delayed physical development and various malformations involving the head, face and limbs. The severity of symptoms is variable.
  • Costello syndrome: A rare genetic disorder characterized by papillomas which may become malignant.
  • Crome syndrome: A very rare disorder characterized by various abnormalities including mental retardation, epilepsy and eye and kidney problems.
  • De Barsy Syndrome: A rare inherited disorder characterized by loose, inelastic skin, involuntary limb movements, cloudy corneas and other abnormalities.
  • Deletion 22q11: A rare chromosomal disorder where a small piece of genetic material is missing from chromosome 22 at the q11 location.
  • Deletion 5p: A rare chromosomal disorder involving deletion of the genetic material from the short arm (p) of chromosome 5 which results in various abnormalities. The resulting condition is often called Cri-du-Chat Syndrome and features may vary somewhat depending on the size and location of the portion of duplicated genetic material.
  • Depressive disorders: Depression or its various related conditions.
  • Desbuquois syndrome: A rare condition characterized by short-limbed dwarfism, characteristic facial features and skeletal abnormalities.
  • Developmental delay due to 2-methylbutyryl-CoA dehydrogenase deficiency: A very rare genetic disorder where an enzyme deficiency prevents the break down of certain proteins into energy and results in a harmful accumulation of acids in the blood and body tissues. More specifically, there is a deficiency of an enzyme (2-methylbutyryl-coenzyme A dehydrogenase) needed to convert the amino acid isoleucine into energy. 2-methylbutyrylglycine levels build up in the body and may cause damage. Symptoms vary according to the degree of enzyme deficiency - can range from asymptomatic to life-threatening.
  • DiGeorge syndrome: 22q11.2 deletion syndrome is a genetic disorder which can result in a vast array of symptoms. Various names have been used to describe different manifestations of the syndrome. Di George Syndrome primarily involves an underdeveloped thymus and parathyroid glands which results in lowered immunity low blood calcium levels respectively. Another primary feature is heart defects. Various other variable features are also present. It is not uncommon for patients to have more than one of the 22q11.2 deletion syndrome subtypes which can make diagnosis confusing - other subtypes include Sphrintzen syndrome, Caylor cardiofacial syndrome and CATCH 22.
  • Dibasic aminoaciduria type 1: A rare disorder where the kidney excretes excessive amounts of certain amino acids (lysine, ornithine and arginine.
  • Dihydropyrimidine dehydrogenase deficiency: A metabolic error where a deficiency of an enzyme called dihydropyrimidine dehydrogenase prevents the normal metabolism of certain proteins. High levels of certain proteins are excreted in the urine. The enzyme is also needed the breakdown a chemotherapy drug called 5-flurouracil and its absence can result in a severe toxicity reaction.
  • Down Syndrome: A chromosome syndrome causing physical effects and mental retardation.
  • Dubowitz Syndrome: A rare genetic and developmental disorder characterized by infantile eczema, small stature, microcephaly and peculiar facial features.
  • Duplication 9p partial: A very rare genetic disorder where a portion of the genetic material on the short arm (p) of chromosome 9 is duplicated which results in various abnormalities. The type and severity of symptoms varies depending on the size and location of the genetic material involved.
  • Dyslexia: Dyslexia is a name for a condition where people have difficulty with reading and writing. People with dyslexia have normal intelligence and are not in any way mentally retarded or intellectually challenged. The difficulty with certain tasks is believed to be related to problems with perception capability in certain parts of the brain. Researchers have discovered that there are a number of genes linked to an increased susceptibility to dyslexia.
  • Dysosteosclerosis: A rare inherited condition characterized by bone development abnormalities (excessive hardening of bone and flattened vertebrae), characteristic facial features. Excessive bone growth at the base of the skull can damage the optic nerves and affect vision.
  • Emery-Dreifuss muscular dystrophy, X-linked: A muscle wasting disorder mainly involving the muscles in the arms, legs, face, neck, spine and heart. Symptoms generally only occur in males but female carriers may have some symptoms.
  • Faciocardiorenal syndrome: A rare syndrome characterized by a variety of abnormalities such as kidney anomaly, mental retardation, unusual facial features, heart problems and joint problems. Infant death or stillbirth may occur in some cases.
  • Farber's disease: A rare inherited biochemical disorder involving the deficiency of an enzyme called ceramidase resulting in the harmful accumulation of certain chemicals in the body which causes damage and inflammation.
  • Filippi Syndrome: A very rare disorder involving finger and toe abnormalities, a small head, characteristic face and physical and mental retardation. The number of digits involved and extent of webbing between digits is variable as are many of the other features.
  • Floating Harbor Syndrome: A rare genetic disorder characterized by growth deficiency, typical facial appearance and speech delay.
  • Focal dermal hypoplasia: A rare genetic disorder characterized by bone, skin, teeth and pigmentation abnormalities as well as asymmetry of the face, trunk and extremities.
  • Fragile-X Syndrome: A rare inherited characterized by various physical anomalies as well as mental retardation. The symptoms are milder in females.
  • Frontometaphyseal dysplasia: A rare genetic disorder characterized by craniofacial abnormalities, skeletal abnormalities, hearing problems and wasting of arm and leg muscles.
  • Fucosidosis: A rare progressive biochemical disorder involving deficiency of an enzyme (alpha-fucosidase) which results in accumulation of certain chemicals (glycosphingolipids) in the central nervous system and other body tissues.
  • GOMBO syndrome: A rare syndrome characterized by retarded growth, eye abnormalities, short fingers and mental deficiency (oligophrenia).
  • Galloway-Mowat Syndrome: A condition which is characterized by microcephaly, hiatal hernia and nephrotic syndrome
  • Gangliosidosis GM1 type 3: A rare biochemical disorder involving a deficiency of an enzyme (beta-galactosidase A) which results in the accumulation of harmful chemicals (GM1 gangliosides) in the central nervous system and other body tissues. Type III involves a lesser degree of accumulation than type II or I.
  • Giant axonal neuropathy: A rare genetic disorder characterized by incoordination, vision problems and dementia caused by abnormalities of a nerve cell component.
  • Glucose transport defect, blood-brain barrier: A rare metabolic disorder involving a deficiency of a molecule needed to transport glucose (GLUT1). The glucose is unable to be transported from the blood and into the brain and cerebrospinal fluid. Sugar transport to the brain is essential for normal development. The blood sugar level remains normal. Fasting exacerbates symptoms which can very in severity depending on the degree of deficiency.
  • Glucosephosphate isomerase deficiency: A rare inherited condition where a lack of the enzyme glucosephosphate isomerase causes red blood cells to be destroyed prematurely (hemolytic anemia).
  • Glut-1 Deficiency Syndrome: A condition which is characterized by a deficiency of the GLUT-1 transported of cells
  • Glutaricaciduria type 1: A rare inherited metabolic disorder where a genetic mutation results in the deficiency of an enzyme called glutaryl-CoA dehydrogenase which is required to metabolise certain amino acids (lysine, hydroxylysine and tryptophan). Problems occur when these metabolites build up in the body and cause neurological problems. Symptoms often develop following an acute infection or fasting. The severity of the condition is highly variable from development of neurological symptoms during infancy to asymptomatic adults. The degree of enzyme deficiency will usually determine the severity.
  • Herpes, Neonatal: Neonatal herpes is the infection of a newborn with the herpes virus within the first six weeks of life. The virus may be transmitted from the mother to the baby while it is still in the uterus or during delivery. The risk of transmitting the virus is highest if genital herpes is contracted during the late stages of the pregnancy. A mother with long standing or recurring herpes infection usually has sufficient antibodies to the virus to prevent the infant becoming infected. Neonatal herpes can also be contracted when an infant comes into contact with an infected person e.g. being kissed by and adult with cold sores. A cesarean birth may be advised for mothers who have active genital lesions.
  • Herpes, Neonatal -- Central Nervous System Infection: Central nervous system herpes infection in neonates is a herpes infection of the central nervous system (brain, spinal cord) that develops in infants within the first six weeks of life. The virus may be transmitted from the mother to the baby while it is still in the uterus or during delivery. The risk of transmitting the virus is highest if genital herpes is contracted during the late stages of the pregnancy. A mother with long standing or recurring herpes infection usually has sufficient antibodies to the virus to prevent the infant becoming infected. Neonatal herpes can also be contracted when an infant comes into contact with an infected person e.g. being kissed by and adult with cold sores. A cesarean birth may be advised for mothers who have active genital lesions. Central nervous system infection will occur in nearly three quarters of infants with a herpes infection.
  • Herpes, Neonatal -- Disseminated: Disseminated neonatal herpes is a widespread infection of a newborn with the herpes virus within the first six weeks of life. The virus may be transmitted from the mother to the baby while it is still in the uterus or during delivery. The risk of transmitting the virus is highest if genital herpes is contracted during the late stages of the pregnancy. A mother with long standing or recurring herpes infection usually has sufficient antibodies to the virus to prevent the infant becoming infected. Neonatal herpes can also be contracted when an infant comes into contact with an infected person e.g. being kissed by and adult with cold sores. A cesarean birth may be advised for mothers who have active genital lesions. Brain infection will occur in over half of infants with the disseminated form.
  • Holoprosencephaly: A rare disorder where abnormalities of the fetal forebrain development lead to various birth defects.
  • Hoyeraal-Hreidarsson syndrome: A very rare syndrome characterized mainly by retarded growth, a small head, anemia, immunodeficiency and an underdeveloped brain (cerebellum).
  • Human HOXA1 Syndromes: Human HOXA1 syndromes are very rare conditions caused by genetic defects involving the HOXA1 gene. The severity of the condition is highly variable depending on the extent of the defect and inheritance pattern. The most severe form is Bosley-Salih-Alorainy syndrome which involves a homozygous mutation. Other manifestations of the genetic defect are Athabaskan Brainstem Dysgenesis syndrome and Navajo Brainstem syndrome. The gene is involved in the development of the cardiovascular system, inner ear and the hindbrain so defects tend to involve mainly these parts of the body.
  • Hydrocephalus: A rare condition where the normal flow of cerebrospinal fluid is impaired by dilated brain ventricles which causes the fluid to accumulate in the skull and hence result in increased brain pressure.
  • Hyperornithinemia-hyperammonemia-homocitrullinuria syndrome: A very rare inherited metabolic disorder where ammonia builds up in the body due to a defect in the transport of ornithine which prevents ammonia being converted to urea and being excreted through the urine. The severity of the condition is variable.
  • Hypochondroplasia: A rare genetic disorder characterized by short stature which becomes more obvious during and after childhood.
  • I cell disease: A rare inherited biochemical disorder characterized by the harmful accumulation of chemicals (glycoproteins and glycoplipids) due to the deficiency of an enzyme (UDP-N-acetylglucosamine-I-phosphotransferase).
  • Inborn amino acid metabolism disorder: A group of inherited disorders where the body is not able to metabolize amino acids consumed in the diet. Amino acids are a part of carbohydrates, fats and proteins and are metabolized in order to provide energy or to make other needed compounds. There are many steps involved in metabolism and the severity can be greatly variable depending on the exact nature of the disorder.
  • Incontinentia Pigmenti: A rare genetic skin pigmentation disorder characterized by eye, teeth, bone, nail and hair malformations as well as central nervous abnormalities and mental deficiency.
  • Intellectual impairment: The impairment of ones cognition
  • Intellectual or developmental disabilities: Disorders of physical or intellectual development.
  • Jackson-Weiss Syndrome: A rare inherited disorder involving bone abnormalities such as fusion of upper foot bones and premature fusion of skull bones which prevents the skull from growing normally. Symptoms can range from mild to severe.
  • Jacobsen syndrome: A very rare chromosomal disorder involving the absence of a portion of chromosome 11q. The range and severity of symptoms is determined by the size of the portion that is deleted.
  • Johanson-Blizzard Syndrome: A rare genetic disorder involving a range of abnormalities including a characteristic beak-like small nose, hypothyroidism and deafness.
  • Joubert Syndrome: A rare neurological disorder where there is a defect in the part of the brain that controls coordination and balance.
  • Kernicterus: A rare condition involving high blood levels of bilirubin which can also accumulate in the brain and lead to neurological problems.
  • Klinefelter syndrome: A genetic condition where males have at least one extra X chromosome or extra copies of both the X and Y chromosomes in each cell. Normally male cells contain one X and one Y chromosome in each cell. The condition is not inherited but is a result of problems during cell division. Klinefelter syndrome variants is a more severe form of the condition as it involves more than one extra X or X and Y chromosome in each cell.
  • Landau-Kleffner Syndrome: A neurological disorder which results in aphasia, epileptic seizures and inability to recognize sounds.
  • Language problems: Symptoms affecting language processing.
  • Lathosterolosis: A very rare disorder where an enzyme (sterol C5-desaturase) deficiency prevents the normal synthesis of cholesterol in the body. The deficiency causes various malformations, mental retardation and liver disease.
  • Laurence-Moon Syndrome: A rare inherited disorder characterized by vision loss, impaired hormone production, mental retardation and spastic paraplegia.
  • Lead poisoning: A type of heavy metal poisoning caused by excessive exposure to lead.
  • Lennox-Gastaut Syndrome: A form of epilepsy that occurs mostly in preschool-aged children and is characterized mainly by absences.
  • Lenz Microphthalmia Syndrome: A condition which is characterized by an abnormally small eye
  • Leprechaunism: A very rare genetic disorder characterized by insulin resistance which leads to growth delay and endocrine system abnormalities.
  • Lesch-Nyhan syndrome: Inherited biochemical disorder of purine metabolism caused by the virtual absence of an enzyme called hypoxanthine-guanine phosphoribosyltransferase or HPRT.
  • Leucinosis: A term used to describe high levels of leucine in the body. It is associated with a metabolic disorder called maple syrup urine disease where there is a deficiency of an enzyme needed to break down leucine so it builds up within the body.
  • Lowe Syndrome: An X linked condition characterized by vitamin D deficiency and causing an oculocerebrorenal syndrome
  • Lowry-Maclean syndrome: A very rare syndrome characterized mainly by mental retardation, retarded growth, glaucoma, congenital heart defects and premature fusion of skull bones.
  • Lowry-Wood syndrome: A rare syndrome characterized by a small head, rapid involuntary eye movements (nystagmus) and abnormal development of the ends of long bones where growth occurs.
  • Lujan-Fryns syndrome: A rare genetic disorder characterized by mental retardation and marfanoid habitus (features of Marfan's syndrome).
  • MELAS: A mitochondrial disorder characterized by stroke-like episodes, headaches, vomiting and other neurological symptoms.
  • Maple syrup urine disease: A very rare inherited metabolic disorder involving abnormal metabolism of branched chain amino acids (leucine, isoleucine and valine) and resulting in severe illness which generally leads to death if not treated. Other milder variants of the disease do exist and tend to occur as late as childhood. Even mild form can result in mental and physical retardation if untreated.
  • Martsolf syndrome: A rare inherited condition characterized by mental retardation, cataracts, small head and hypogonadism (reduced production of hormones by ovaries or testes).
  • Megalencephalic leukoencephalopathy with subcortical cysts: A very rare syndrome characterized mainly by a progressive brain destruction that causes mental retardation and incoordination that starts early in life.
  • Mental illness: Any psychological syndrome
  • Mental retardation -- dysmorphism -- hypogonadism -- diabetes: A very rare syndrome characterized mainly by mental retardation, hypogonadism, diabetes and facial and skull abnormalities.
  • Methylene tetrahydrofolate reductase deficiency: A inborn error of metabolism where an inherited deficiency of methylene tetrahydrofolate reductase causes symptoms of ranging severity - from asymptomatic to severe neurological degeneration and premature death.
  • Microcephaly -- oculo-digito-esophageal-duodenal syndrome (MODED): A very rare syndrome characterized mainly by a small head and gastrointestinal, eye, finger, and toe abnormalities.
  • Miller-Dieker syndrome: A rare genetic disorder characterized by a smooth brain surface. The condition occurs because of deletion of genetic material from the short arm of chromosome 17 ath a particular location (17p13.3).
  • Mohr-Tranebjaerg syndrome: A very rare syndrome characterized mainly by nerve degeneration. Deafness usually occurs early in life.
  • Mowat-Wilson syndrome: A very rare syndrome characterized mainly by mental retardation, a small head, characteristic facial appearance and various other abnormalities.
  • Mucolipidosis III: A rare metabolic disorder where deficiency of a particular enzyme leads to the buildup of mucopolysaccharides and mucolipids in the body which is harmful to the body and leads to premature death.
  • Mucolipidosis IV: A condition which is characterized by the accumulation of both glycoaminoglycans and lipids in tissues
  • Mucopolysaccharidosis VII: Disorder of mucopolysaccharide metabolism.
  • Multiple Sulfatase Deficiency: A condition characterized by multiple sulfatase deficiencies
  • Multiple pterygium syndrome: A very rare disorder characterized by webbing of various parts of the body, contractures, short stature, fusion of neck vertebrae and facial anomalies.
  • Myhre Syndrome: A very rare inherited disorder characterized by retarded growth, mental retardation, bone abnormalities and distinctive facial features.
  • Myotonic Dystrophy: An inherited disorder characterized by progressive muscle weakness and wasting as well as eye defects, heart abnormalities and other anomalies. The severity of the condition is greatly variable. There are two type of myotonic dystrophy with type 1 being more severe than type 2.
  • NOMID syndrome: A rare autoinflammatory disease characterized by fever, rash, arthritic changes, eye problems and chronic meningitis.
  • Neurofibromatosis syndrome: A rare genetic disorder characterized by areas of increased and decreased skin pigmentation and the development of many non-cancerous nerve and skin tumors some of which may eventually become malignant.
  • Neurofibromatosis syndrome Type II: A rare genetic disorder characterized by areas of increased and decreased skin pigmentation, acoustic neuromas and the development of many noncancerous nerve and skin tumors some of which may eventually become malignant - it is a more severe form of type I neurofibromatosis.
  • Neurofibromatosis-2: Genetic disorder often leading to tumors on nerves.
  • Neuropathy -- ataxia -- retinitis pigmentosa: A rare inherited disorder where defects in the energy producing part of cells affects the nervous system and causes symptoms such as muscle and vision problems. Severity and rang of symptoms are variable.
  • Neuropathy ataxia and retinis pigmentosa: A rare inherited disorder where defects in the energy producing part of cells affects the nervous system and causes symptoms such as muscle and vision problems. Severity and rang of symptoms are variable.
  • Norrie Disease: A rare form of blindness that occurs at birth or soon after due to eye defects. The severity and range of symptoms is variable.
  • Oculodigitoesophagoduodenal syndrome: A very rare syndrome characterized mainly by a small head and gastrointestinal, eye, finger, and toe abnormalities.
  • Ohtahara Syndrome: A very rare syndrome characterized mainly by epilepsy that starts within a month of birth.
  • Orofaciodigital syndrome type1: A rare genetic disorder characterized by variable malformations of the face, digits and inside the mouth. Type 1 is distinguished from the other types of this condition by the presence of polycystic kidneys and a X-linked dominant inheritance.
  • Osteoporosis-pseudoglioma syndrome: A rare genetic disorder characterized by early onset of osteoporosis (during childhood) and loss of vision resulting from retinal detachment due to a retinal pseudoglioma (inflammatory eye condition).
  • Oto-palato-digital syndrome, type 2: A rare genetic disorder characterized by head, face, mouth and bone abnormalities.
  • PUPPPS: Pruritic urticarial papules and plaques of pregnancy
  • Paraplegia -- brachydactyly -- cone-shaped epiphysis: A very rare syndrome characterized mainly by paraplegia, short fingers and bone abnormalities. The paraplegia progresses slowly.
  • Periodic hyperlysinemia: A rare genetic disorder where the body lacks enzymes to metabolize lysine which then causes a harmful builds up of lysine and ammonia in the body.
  • Pitt-Rogers-Danks syndrome: A rare genetic condition characterized by reduced fetal growth, mental retardation and distinctive facial features.
  • Potocki-Shaffer syndrome: A very rare syndrome caused by the absence of a portion of chromosome 11p and characterized mainly by bone growths, enlarged fontanel and parietal foramina.
  • Prader-Willi syndrome: A rare genetic disorder characterized by reduced muscle tone, obesity and small hands and feet.
  • Proteus Syndrome: A rare genetic disorder characterized by overgrowth of bones, fatty tissues and skin in various parts of the body.
  • Psychiatric disorders: Any condition that affects ones mind
  • Purine nucleoside phosphorylase (PNP) deficiency: A condition which is characterized by a deficiency of purine nucleoside phosphorylate
  • Pyruvate dehydrogenase deficiency: An inherited carbohydrate metabolism disorder where a deficiency of pyruvate dehydrogenase results in metabolic acidosis and mental retardation as well as other neurological symptoms. The condition may be mild or severe. The condition is exacerbated by eating high carbohydrate meals and stress.
  • Ramon Syndrome: A rare genetic condition characterized by cherubism, enlarged gums, epilepsy, mental deficiency and excessive body hair (hypertrichosis).
  • Reading symptoms: Problems with reading ability
  • Renpenning syndrome 1: A very rare genetic disorder that affects males and is characterized mainly by mental retardation and facial anomalies.
  • Roberts Pseudothalidomide Syndrome:
  • Rubinstein-Taybi Syndrome: A rare congenital disorder characterized by very small stature, broad thumbs and toes, slanted palpebral fissures and hypoplastic maxilla.
  • SBCAD deficiency: A very rare genetic disorder where an enzyme deficiency prevents the break down of certain proteins into energy and results in a harmful accumulation of acids in the blood and body tissues. More specifically, there is a deficiency of an enzyme (2-methylbutyryl-coenzyme A dehydrogenase) needed to convert the amino acid isoleucine into energy. 2-methylbutyrylglycine levels build up in the body and may cause damage. Symptoms vary according to the degree of enzyme deficiency - can range from asymptomatic to life-threatening.
  • Saethre-Chotzen syndrome, chromosome 7 p15.3p21.3: A rare genetic disorder characterized by finger anomalies and premature joining of certain skull bones during development which has an impact on the shape of the head and face. There appears to be considerably variability of symptoms and clinical features of the disorder depending on the exact size and location of the portion of chromosomal material deleted. In this particular form, the chromosomal material deleted is located on chromosome 7 p15.3p21.3.
  • Saethre-Chotzen syndrome, chromosome 7 p21.1p21.3: A rare genetic disorder characterized by finger anomalies and premature joining of certain skull bones during development which has an impact on the shape of the head and face. There appears to be considerably variability of symptoms and clinical features of the disorder depending on the exact size and location of the portion of chromosomal material deleted. In this particular form, the chromosomal material deleted is located on chromosome 7 p21.1p21.3.
  • Say-Meyer syndrome: A very rare syndrome characterized mainly by short stature, developmental delay and trigonocephaly (premature fusion of skull bones giving the forehead a triangular shape).
  • Schizencephaly: A very rare disorder where the brain fails to develop normally and slits or clefts form in the brain. They type and severity of symptoms is determined by the degree of abnormality.
  • Scott Craniodigital Syndrome: A condition which is characterized by deformities of the cranium and fingers
  • Seemanova-Lesny syndrome: A rare disorder characterized by spasticity, seizures, absent abdominal reflexes, small head and mental retardation.
  • Septo-Optic Dysplasia: A rare birth defect characterized by impaired vision and pituitary deficiency.
  • Septooptic dysplasia -- digital anomalies: A very rare syndrome characterized mainly by finger and toe abnormalities as well as abnormal development of the optic nerve and pituitary gland. Antenatal exposure to sedatives may be a factor in the cause of the disorder.
  • Shprintzen omphalocele syndrome: A rare syndrome characterized mainly by abnormal development of the pharynx and larynx which can result in a narrowed airway. Protrusion of intestines through the belly button also occurs. The voice is high pitched and spinal curvature and learning problems are other common symptoms.
  • Shprintzen syndorme: An inherited syndrome of cardiac defects and craniofacial anomalies and various other abnormalities.
  • Shprintzen-Golberg craniosynostosis: A very rare syndrome characterized by premature fusion of skull bones and a Marfanoid appearance, skeletal anomalies and learning problems.
  • Shprintzen-Goldberg syndrome: A rare malformations syndrome characterized by abnormalities such as small head, eye problems, poor muscle tone, hearing problems and Hirschsprung megacolon where defective intestinal muscles are unable to move stool efficiently through the intestines.
  • Shwachman-Diamond Syndrome:
  • Sialidosis type 1: A rare inherited condition where deficiency of an enzyme called neuraminidase results in epilepsy, ataxia and vision problems as well as characteristic cherry red spots in the macula of the eye. Symptoms may be exacerbated by factors such as smoking and menstrual cycles.
  • Sjogren-Larsson syndrome: A rare inherited neurological and skin disorder characterized by mental retardation, spastic paraplegia and thickened scaly skin (ichthyosis). The condition involves a deficiency of fatty alcohol oxidoreductase which causes an accumulation of long-chain fatty alcohols.
  • Smith-Lemli-Opitz Syndrome: A rare genetic condition involving a severe defect in the process of cholesterol synthesis resulting in low cholesterol levels in cells but high levels of the chemicals that are made into cholesterol.
  • Smith-Magenis Syndrome: A rare syndrome characterized by various developmental problems as well as various physical defects primarily affecting the head and the face.
  • Soto's Syndrome: A rare hereditary disorder characterized by excessive growth during the first few years of life as well as various other mental and physical anomalies.
  • Speech and communication conditions: Medical conditions affecting speech or the ability to communicate.
  • Spina bifida: A birth defect where the spinal vertebrae do not completely enclose the spinal cord often resulting in various degrees of nerve damage.
  • Spondylometaphyseal dysplasia, X-linked: A rare disorder characterized by spine and long bone abnormalities and facial anomalies. The disorder is inherited in a X-linked manner which means that males exhibit the full extent of the symptoms whereas female carriers often have only mild symptoms.
  • Sturge-Weber Syndrome: A rare genetic disorder characterized by excessive blood vessel growth, calcium accumulation inside the brain and seizures.
  • Stuttering: Speech difficulty involving repetition
  • Subependymal nodular heterotopia: A rare inherited disorder where a part of the brain tissue is misplaced during development. More specifically, nodules of the abnormal tissue is found in the subependymal part of the brain.
  • Succinic Semialdehyde Dehydrogenase Deficiency: A condition which is characterized by a deficiency of succinic semialdehyde dehydrogenase
  • Sulfatidosis juvenile, Austin type: A very rare metabolic disorder where all the sulfatase enzymes are impaired resulting in a variety of physical and developmental abnormalities.
  • Tay Sachs Disease: A condition which is causes GM2 gangliosidosis
  • Thyroid agenesis: A rare disorder where the thyroid fails to develop resulting in hypothyroidism from birth.
  • Timothy syndrome: A rare syndrome characterized by webbed fingers and a heart defect. Most affected individuals die during early childhood or infancy.
  • Triose phosphate-isomerase deficiency: A very rare inherited condition involving a deficiency of triose phosphate-isomerase.
  • Trisomy 18 mosaicism: A rare genetic chromosomal syndrome where the child has an extra third copy of chromosome 18 in only some of the body's cells. It is a less severe form of Edwards syndrome - the most severe form involves and extra copy of chromosome 18 in all of the body's cells. The severity of the condition is highly variable depending on how many of the body's cells are involved.
  • Trisomy 8 mosaicism: A very rare chromosomal disorder where there is an extra copy of chromosome 8 in some of the body's cells. Some cases with this chromosomal abnormality have no clinical symptoms. The presence of abnormalities in some cases is dependent on which body cells contain the chromosomal defect.
  • Tuberous sclerosis: A rare genetic disorder characterized by harmartomatous skin nodules, seizures, phakomata and bone lesions.
  • Tuberous sclerosis, type 1: A rare genetic disorder with a variety of abnormalities such as seizures, mental retardation, skin lesions and nodules in various body tissues and organs.
  • Turner Syndrome: Rare chromosome syndrome with one X but no second X or Y chromosome.
  • Varadi Papp syndrome: A syndrome characterised by deformities of the oral-facial-digital areas
  • Vascular malformations of the brain: Conditions affecting the brain blood vessels. The type and severity of symptoms is determined by the type, location and extent of the malformation. There are six types of vascular malformations of the brain: telangiectasis, venous malformations, cavernous malformations, arteriovenous malformations, vein of Galen malformation and mixed malformations.
  • Velocardiofacial syndrome: A genetic disorder which can present with a wide range of phenotypic manifestations which has lead to a number of different names being assigned to the various presentations e.g. DiGeorge Syndrome and Cayler Anomaly Face Syndrome. There are nearly 200 different symptoms that can occur and the severity of the condition is also highly variable depending on the nature and severity of the symptoms that are present.
  • WAGR Syndrome: A syndrome that is due to the deletion of chromosome 11.
  • Waardenburg syndrome, type 3: A rare syndrome involving deafness, pigmentation and musculoskeletal abnormalities
  • Walker-Warburg Syndrome: A rare inherited disorder characterized by brain malformations and retinal and muscle abnormalities.
  • Wieacker-Wolff Syndrome:
  • Williams Syndrome: A syndrome characterised by mental retardation, facial abnormalities and emotional instability
  • Worster Drought syndrome: A mild form of tetraplegic cerebral palsy
  • Wrinkly skin syndrome: A very rare genetic disorder characterized by wrinkly skin that occurs primarily on the palms and soles but can occur on other parts of the body. The condition is also associated with various other abnormalities.
  • Writing symptoms: Problems with writing ability
  • Young Hughes syndrome: A sex linked condition that is characterised by mental retardation and hypogonadism
  • Yunis Varon syndrome: A multisystem genetic disease that affects the skeletal system in particular
  • Zunich neuroectodermal syndrome: A very rare genetic syndrome characterized by a range of symptoms such as colobomas of the eye, heart defects, ichthyosiform dermatosis, mental retardation and ear defects.

 

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