Tuberous Sclerosis

Definition

Definition of Tuberous Sclerosis
Tuberous sclerosis or tuberous sclerosis complex (TSC) is a rare multi-system genetic disease that causes non-malignant tumors to grow in the brain and on other vital organs such as the kidneys, heart, eyes, lungs, and skin. A combination of symptoms may include seizures, developmental delay, behavioral problems, skin abnormalities, lung and kidney disease. TSC is caused by a mutation of either of two genes, TSC1 and TSC2, which code for the proteins hamartin and tuberin respectively. These proteins act as tumor growth suppressors, agents that regulate cell proliferation and differentiation.

Symptoms

Symptoms of Tuberous Sclerosis
Tuberous sclerosis symptoms include noncancerous lesions that grow in many parts of the body, such as in the skin, brain and kidneys. Lesions may be referred to as hamartias or hamartomas. Sometimes lesions grow in other parts of the nervous system or in the heart, lungs or the light-sensitive tissue at the back of the eye (retina). Tuberous sclerosis signs and symptoms vary, depending on where the lesions develop:

1. Skin problems, such as light patches and thickened skin
2. Seizures
3. Behavior problems
4. Learning disabilities
5. Mental retardation
6. Kidney problems

Causes

Causes of Tuberous Sclerosis
Tuberous sclerosis is inherited. Changes (mutations) in two genes, TSC1 and TSC2, are responsible for most cases of the condition.

Only one parent needs to pass on the mutation for the child to get the disease. However, most cases are due to new mutations, so there usually is no family history of tuberous sclerosis.

This condition is one of a group of diseases called neurocutaneous syndromes. Both the skin and central nervous system (brain and spinal cord) are involved.

Diagnosis

Diagnosis of Tuberous Sclerosis
There are no pathognomonic clinical signs for tuberous sclerosis. Many signs are present in individuals who are healthy (although rarely), or who have another disease. A combination of signs, classified as major or minor, is required in order to establish a clinical diagnosis.

Treatment

Treatment of Tuberous Sclerosis
There is no specific treatment for tuberous sclerosis. Because the disease can differ from person to person, treatment is based on the symptoms. Medications are needed to control seizures, which is often difficult. Depending on the severity of the mental retardation, the child may need special education.

Prognosis

Prognosis of Tuberous Sclerosis
Children with mild tuberous sclerosis usually do well. However, children with severe retardation or uncontrollable seizures usually do poorly. 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 was not diagnosed.

Prevention

Prevention of Tuberous Sclerosis
Genetic counseling is recommended for prospective parents with a family history of tuberous sclerosis. Prenatal diagnosis is available for families with a known DNA mutation. However, tuberous sclerosis often appears as a new mutation, and these cases are not preventable.