Tuberous sclerosis is a group of two genetic disorders characterized by problems with the skin, brain/nervous system, and kidneys. There is also a predisposition to tumors. The diseases are named after a characteristic abnormal growth in the brain, which takes the shape of a tuber or root.
Tuberous sclerosis is inherited as an autosomal dominant trait (only one parent must pass on the bad gene for the child to get the disease). However, a high percentage of cases are due to new mutations (which occur in the sperm or egg of one of the parents), so there usually is no family history of the disease.
It is one of a group of diseases described as neuro-cutaneous syndromes, because of large involvement of both the skin and the central nervous system (brain and/or spinal cord).
The symptoms of tuberous sclerosis vary considerably: from minimally affected people with normal intelligence and no seizures, to severely affected people with profound retardation and frequent, difficult-to-control seizures or serious tumors. Mutations in two genes, TSC1 and TSC2, are responsible for tuberous sclerosis.
Severely affected people may develop seizures shortly after birth. These are characterized by spasms (hypsarrhythmia). Mental retardation becomes evident as infants begin to miss their normal developmental milestones.
Infants may have heart tumors (rhabdomyoma), which can be detected by ultrasound. These tumors may grow or shrink and usually do not cause problems.
Several different skin lesions are common in tuberous sclerosis.
The incidence is approximately 1 in 25,000-30,000 births. There are no known risk factors other than having a parent with tuberous sclerosis. In that case, each child has a 50% chance of inheriting the disease.
There is no specific treatment for tuberous sclerosis. Treatment is specific to the symptoms. Medications are required for controlling seizures, which is often difficult. The need for special schooling or care is determined by the severity of mental retardation.
Adenoma sebaceum (small growths) on the face may be removed by laser treatment. These lesions tend to recur and repeat treatments will be necessary.
Rhabdomyomas commonly disappear after puberty, so surgery is usually not necessary. Regular ultrasound checks of the kidneys are an important screening tool for adults, to make sure there is no tumor growth.
For additional information and resources, contact the Tuberous Sclerosis Alliance at 800-225-6872.
Children with mild tuberous sclerosis usually do well. Occasionally, when a severely affected child is born, the parents are examined, and one of them is found to have had a mild case of tuberous sclerosis that escaped detection.
Children with profound retardation or uncontrollable seizures usually do poorly. Although numerous benign tumors occur in this disease, some, such as renal or brain tumors, can become malignant.
Notify your health care provider if either side of the family has a history of tuberous sclerosis. Since tuberous sclerosis also appears as a spontaneous mutation, call your health care provider if you notice symptoms suggestive of tuberous sclerosis in your child. Call a geneticist if your child is diagnosed with cardiac rhabdomyoma, as tuberous sclerosis is the leading cause of this tumor.
Genetic counseling is recommended for prospective parents with a family history of tuberous sclerosis. Prenatal diagnosis may be available for families with a known DNA mutation. However, tuberous sclerosis frequently appears as a new mutation; these cases are not preventable.