Inheritance and Genetics of Prader-Willi syndrome
Prader-Willi syndrome: Genetics Information
Genetics of Prader-Willi syndrome:
PWS is caused by the absence of segment 11-13 on the long arm of the paternally derived chromosome 15. In 70-80% of PWS cases, the region is missing due to a deletion. Certain genes in this region are normally suppressed on the maternal chromosome, so, for normal development to occur, they must be expressed on the paternal chromosome. When these paternally derived genes are absent or disrupted, the PWS phenotype results. When this same segment is missing from the maternally derived chromosome 15, a completely different disease, Angelman syndrome, arises. This pattern of inheritance --- when expression of a gene depends on whether it is inherited from the mother or the father --- is called genomic imprinting. The mechanism of imprinting is uncertain, but, it may involve DNA methylation.
(Source: Genes and Disease by the National Center for Biotechnology)
About inheritance and genetics:
Inheritance of Prader-Willi syndrome refers to whether the condition is inherited
from your parents or "runs" in families.
The level of inheritance of a condition depends
on how important genetics are to the disease.
Strongly genetic diseases are usually inherited,
partially genetic diseases are sometimes inherited,
and non-genetic diseases are not inherited.
For general information, see Introduction to Genetics.