What Is Familial Dysautonomia?
Familial dysautonomia, caused by harmful genetic changes (mutations) in the ELP1 gene (formerly known as the IKBKAP gene), is an inherited condition that causes nerve cells to deteriorate. It affects the autonomic nervous system, which controls involuntary actions such as breathing, tear production, blood pressure, and body temperature. It also affects the sensory nervous system, which controls senses such as the abilities to perceive taste, pressure, pain, and temperature.
Symptoms associated with the condition may first appear in infancy. Examples of these symptoms include feeding problems, poor growth and muscle tone, lack of tears, frequent lung infections, and marked fluctuations in body temperature. Children with the condition may also hold their breath for long periods of time, which may cause fainting or make their lips or skin appear blue. This behavior usually ends by the age of six. While some children may not have any delays in development, individuals usually experience some delays in milestones such as walking and speech.
As children become older they may develop symptoms including bed-wetting, vomiting, reduced sensitivity to temperatures and pain, decreased ability to taste, poor balance, abnormal curvature of the spine, easily fractured bones, and kidney and heart problems. They can also have trouble regulating blood pressure and commonly experience a sharp drop in blood pressure when they stand up, which can cause blurred vision, dizziness, or fainting. This can also lead to episodes of high blood pressure when nervous or excited.
By adulthood, individuals with familial dysautonomia may have balance problems that prevent them from walking unaided. Other common complications include sleep apnea, lung damage due to repeated infections, poor vision as optic nerves atrophy, and kidney disease. Intellect is usually not affected in individuals with this condition.
How Common Is Familial Dysautonomia?
Familial dysautonomia is found almost exclusively in individuals of Ashkenazi Jewish descent, where it affects approximately 1 in 3,800 individuals. Roughly 1 in 31 Ashkenazi Jews is a carrier of the disease. It is extremely rare in the general population.
How Is Familial Dysautonomia Treated?
There is no cure for the cause of familial dysautonomia. Treatment focuses on relieving its symptoms.
Infants with the condition may need to be fed thickened formula to ensure adequate nutrition and prevent them from inhaling their food. Vomiting crises are treated with IV fluids and anti-nausea medication. Recurrent pneumonia caused by inhaling food or vomit requires daily chest physiotherapy. Older children who experience low blood pressure may require elastic stockings and leg exercises to improve muscle tone and prevent blood from pooling in leg veins. Corneal injuries caused by low tear production may be treated with regular eye drops, soft contact lenses, or in rare cases, surgery. Spinal fusion surgery may be necessary to correct scoliosis. Kidney disease may require dialysis. Sleep apnea is generally treated with a machine to support breathing. Many adults with the condition require walkers or wheelchairs.
What Is the Prognosis for an individual with Familial Dysautonomia?
The average lifespan of an individual with familial dysautonomia is shortened with 60% of individuals with the disease living to age 20.