Definition of Riley-Day syndrome:

Riley-Day syndrome is an inherited disorder that affects nerve function throughout the body. Symptoms are present at birth and grow worse over time.

Causes, incidence, and risk factors:

Riley-Day syndrome is inherited as an autosomal recessive trait, which means that a person must inherit a copy of the malfunctioning gene from each parent in order to develop the condition.

It is seen most often in people of Eastern European Jewish ancestry (Ashkenazi Jews), where the incidence is 1 in 3,700. The disease is caused by mutation of the IKBKAP gene on chromosome 9. It is rare in the general population.