Prevalence and Incidence of Costello syndrome
Prevalance of Costello syndrome:
only about 250 cases of Costello syndrome has been reported worldwide, Genetics Home Reference website ... see also overview of Costello syndrome.
Costello syndrome: Rare Disease
Costello syndrome is listed as a "rare disease" by the Office of
Rare Diseases (ORD) of the National Institutes of Health
(NIH). This means that Costello syndrome, or a subtype of Costello syndrome,
affects less than 200,000 people in the US population.
Ophanet, who are a consortium of European partners,
currently defines a condition rare when if affects 1 person per 2,000.
They list Costello syndrome as a "rare disease".
More information about Costello syndrome is available from Orphanet
About prevalence and incidence statistics:
The term 'prevalence' of Costello syndrome usually refers to the estimated population
of people who are managing Costello syndrome at any given time.
The term 'incidence' of Costello syndrome refers to the annual diagnosis rate,
or the number of new cases of Costello syndrome diagnosed each year.
Hence, these two statistics types can differ:
a short-lived disease like flu can have high annual incidence but low prevalence,
but a life-long disease like diabetes has a low annual incidence but high prevalence.
For more information see about prevalence and incidence statistics.