Disease characteristics
Familial dysautonomia (FD), also known as (Riley-Day syndrome) is an autonomic nervous system disorder, which affects the development and survival of sensory, sympathetic and some parasympathetic neurons in the autonomic and sensory nervous system.

Prevalence
Despite the fact the public and many medical professionals are unfamiliar with familial dysautonomia, it is quite prevalent in Ashkenazi Jews where about 1 in 30 are carriers of the more common FD mutation. In fact its prevalence is similar to the much better-known disorder, Tay-Sachs disease.

Mutation
Familial dysautonomia is caused by a mutation in a protein called IKAP  (IkB kinase complex associated protein) on chromosome 9. Three mutations have been identified where the most common mutation occurs in intron 20 of the donor gene. Conversion of T-->C results in shift splicing that generates an IKAP transcript lacking exon 20. Another less common mutation is a G-->C conversion resulting in P696R.

Testing criteria and symptoms
Being of Ashkenazi Jewish ancestry
Insensitivity to pain, poor growth, inability to produce tears, and labile blood pressure
Frequent vomiting crises, pneumonia, problems with speech and movement, and difficulty swallowing