Familial dysautonomia (FD) is a rare, progressive, recessive genetic disorder of the autonomic nervous system seen primarily in people of Eastern European Jewish descent that affects the development and survival of sensory, sympathetic and some parasympathetic neurons in the autonomic and sensory nervous system.
FD results in variable symptoms, including insensitivity to pain, inability to produce tears, poor growth and labile blood pressure (episodic hypertension and postural hypotension). People with FD have frequent vomiting crises, pneumonia, problems with speech and movement, difficulty swallowing, inappropriate perception of heat, pain and taste as well as unstable blood pressure and gastrointestinal dysmotility.
Originally reported by Drs. Conrad Milton Riley (1913–2005) and Richard Lawrence Day (1905–1989) in 1949, FD is one example of a group of disorders known as hereditary sensory and autonomic neuropathies (HSAN). All HSAN are characterized by widespread sensory dysfunction and variable autonomic dysfunction caused by incomplete development of sensory and autonomic neurons. The disorders are believed to be genetically distinct from each other.