Screening for Familial Dysautonomia

Experts at NYU Langone offer complete care for people who have familial dysautonomia, a rare inherited condition that affects the development of the autonomic and sensory nervous systems. The autonomic nervous system regulates the function of internal organs such as the heart, intestines, and lungs. The sensory system transmits information from the body to the brain, allowing people to sense things such as pain, temperature, and changes in body position or muscle tension.

Failure of these systems can have a wide variety of unusual consequences. For instance, those who have difficultly coordinating their swallowing and balance muscles may have feeding difficulties and repeated injuries. Inability to regulate blood pressure can cause a sudden increase in blood pressure when a person is excited, nervous, or ill, or when they are eating. Just as suddenly, people who have familial dysautonomia may experience a drop in blood pressure when moving from sitting to standing.

Familial dysautonomia is caused by mutations in a gene known as IKBKAP. These mutations occur almost exclusively in people of Ashkenazi (Eastern European) Jewish descent. Some people carry the gene without realizing it. Normally, this gene instructs the body to make a protein—IκB kinase complex associated protein (IKAP)—that is essential for the development and survival of nerve cells.

A person who has one defective IKBKAP gene is a carrier but does not have symptoms of familial dysautonomia. Children who inherit two copies of the defective gene—one from each parent—are born with the condition. However, even if both parents are carriers, there is still a 75 percent chance that the baby may inherit just one copy of the defective gene, or none at all, and remain healthy.

Carrier Screening

Experts at NYU Langone recommend genetic screening for parents who have a family history of familial dysautonomia or if both parents have an Ashkenazi Jewish background. Screening for the IKBAP gene is performed with a blood test to identify the IKBKAP mutation. This test has a reliability of greater than 99 percent.

Prenatal Tests

Prenatal tests, such as amniocentesis or chorionic villus sampling, can help to diagnose familial dysautonomia before your baby is born. Doctors may recommend these tests if you or your partner are carriers of a mutated IKBKAP gene or if either of you have a family history of familial dysautonomia. 

Amniocentesis, which is usually done in the second trimester of pregnancy, may be used to look for the genetic mutation in a small sample of the amniotic fluid that surrounds the unborn child while he or she is in the womb. 

During chorionic villus sampling, which can be performed near the end of the first trimester of pregnancy, the doctor looks for the genetic mutation in a small tissue sample that is removed from the placenta, a temporary organ that carries oxygen and nutrients from a mother to her baby. 

Genetic counselors at NYU Langone can explain the results of these tests and offer treatment options. 

NYU Langone’s Fertility Center offers several family planning options.