Tuberous sclerosis

Definition

Tuberous sclerosis is a group of two genetic disorders that affect the skin, brain/nervous system, kidneys, and heart, and cause tumors to grow. The diseases are named after a tuber- or root-shaped growth in the brain.

Alternative Names

Adenoma sebaceum

Causes

Tuberous sclerosis is inherited. Changes (mutations) in two genes, TSC1 and TSC2, are responsible for 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 neuro-cutaneous syndromes. Both the skin and central nervous system (brain and spinal cord) are involved.

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.

Symptoms

Skin symptoms include:

• Caf-au-lait spots
• Red patches on the face containing many blood vessels (adenoma sebaceum)
• Raised patches of skin with an orange-peel texture (shagreen spots), often on the back
• White areas of skin that look like an ash leaf (ash leaf spots)

Brain symptoms include:

• Developmental delays
• Mental retardation
• Seizures

Other symptoms:

• Heart tumors (rhabdomyoma)
• Kidney tumors
• Pitted dental enamel
• Rough growths under or around the fingernails and toenails
• Rubbery non-cancerous tumors on or around the tongue

The symptoms of tuberous sclerosis vary from person to person. Some people have normal intelligence and no seizures. Others have severe retardation, serious tumors, or difficult-to-control seizures.

Exams and Tests

Signs may include:

• Abnormal heart rhythm (arrhythmia)
• Calcium deposits in the brain
• Non-cancerous "tubers" in the brain
• Rubbery growths on the tongue or gums
• Tumor-like growth (hamartoma) on the retina, pale patches in the eye
• Tumors

Tests may include:

• CT scan of the head
• MRI of the head
• Ultrasound of the kidney
• Ultraviolet light examination of the skin

DNA testing for either of the two genes that can cause this disease (TSC1 or TSC2) is available.

Regular ultrasound checks of the kidneys are an important screening tool, to make sure there is no tumor growth.

Treatment

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 menal retardation, the child may need special education.

Small growths (adenoma sebaceum) on the face may be removed by laser treatment. These growths tend to come back, and repeat treatments will be necessary.

Rhabdomyomas commonly disappear after puberty, so surgery is usually not necessary.

Support Groups

For additional information and resources, contact the Tuberous Sclerosis Alliance at 800-225-6872.

Outlook (Prognosis)

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.

The tumors in this disease tend to be non-cancerous (benign). However, some tumors (such as kidney or brain tumors) can become cancerous.

Possible Complications

• Brain tumors (astrocytoma)
• Heart tumors (rhabdomyoma)
• Severe mental retardation
• Uncontrollable seizures

When to Contact a Medical Professional

Call your health care provider if:

• Either side of your family has a history of tuberous sclerosis
• You notice symptoms of tuberous sclerosis in your child

Call a genetic specialist if your child is diagnosed with cardiac rhabdomyoma. Tuberous sclerosis is the leading cause of this tumor.

Prevention

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.

References

Haslam RHA. Neurocutaneous Syndromes. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 596.

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