A genetic disorder that affects the development and survival of autonomic and sensory nerve cells.
Familial dysautonomia (FD), sometimes called Riley-Day syndrome, is a hereditary sensory and autonomic neuropathy (HSAN). It stems from incomplete development of sensory and autonomic neurons and manifests in widespread sensory and variable autonomic dysfunction (New York University School of Medicine FD Center, 2001). FD is a rare autosomal-recessive disorder occurring largely in Ashkenazi Jews, in whom incidence is about .5-1 per 10,000. The FD gene is located on the long arm of Chromosome 9.