Article: Familial dysautonomia

What is familial dysautonomia?

Familial dysautonomia affects the autonomic nervous system, which controls involuntary actions such as digestion, breathing, tearing, and the regulation of blood pressure and body temperature. This condition also affects the sensory nervous system, which controls activities related to the senses, such as taste and the perception of pain, heat, and cold.

How common is familial dysautonomia?

In populations of individuals with Central or Eastern European (Ashkenazi) Jewish ancestry, familial dysautonomia occurs in about 1 in 3,700 people. This disorder is rare in the general population.

What genes are related to familial dysautonomia?

Mutations in the IKBKAP gene cause familial dysautonomia.

Nearly all individuals with familial dysautonomia have two copies of the same mutation, which causes part of the IKBKAP gene to be skipped when it is copied for production of the IKAP protein. This skipping mutation results in the formation of an abnormally short and poorly functioning IKAP protein. This mutation, however, behaves inconsistently. As a result, some cells produce near normal amounts of functioning IKAP protein, and other cells--particularly cells in the nervous system--have very little functional IKAP protein. Critical activities in brain and nerve cells are probably disrupted by reduced amounts or the absence of functional IKAP protein, leading to the signs and symptoms of familial dysautonomia.

How do people inherit familial dysautonomia?

This condition is inherited in an autosomal recessive pattern, which means two copies of the gene in each cell are altered. Most often, the parents of an individual with an autosomal recessive disorder are carriers of one copy of the altered gene but do not show signs and symptoms of the disorder.