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 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.

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:

• Areas of the skin that are white (due to decreased pigment) and have either an ash leaf or confetti appearance
• 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

Brain symptoms include:

• Developmental delays
• Mental retardation
• Seizures

Other symptoms:

• Pitted tooth enamel
• Rough growths under or around the fingernails and toenails
• Rubbery noncancerous 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 intellectual disabilities or difficult-to-control seizures.

Exams and Tests

Signs may include:

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

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.

• Depending on the severity of the mental disability, the child may need special education.
• Some seizures are controlled with medication (vigabatrin). Other children may need surgery.
• Small growths (adenoma sebaceum) on the face may be removed by laser treatment. These growths tend to come back, and repeat treatments will be needed.
• Rhabdomyomas commonly disappear after puberty, so surgery to remove them is usually not needed.
• Brain tumors can be treated with medicines called mTOR inhibitors (sirolimus, everolimus).
• Kidney tumors are treated with surgery, or by reducing the blood supply using special x-ray techniques. mTOR inhibitors are being studied as another treatment for kidney tumors.

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 mental disability or uncontrollable seizures usually do poorly. 

Sometimes when a child is born with severe tuberous sclerosis, one of the parents is found to have had a mild case of tuberous sclerosis that was not diagnosed.

The tumors in this disease tend to be noncancerous (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 couples who have a family history of tuberous sclerosis and who want to have children.

Prenatal diagnosis is available for families who are known to have a history of this condition. However, tuberous sclerosis often appears as a new DNA mutation, and these cases are not preventable.

References

Sahin M. Neurocutaneous syndromes. In: Kliegman RM, Stanton BF, St. Geme JW, Schor NF, Behrman RE, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa: Saunders Elsevier; 2011: chap 589.

Northrup H, Koenig MK, Au KS. Tuberous sclerosis complex. In: Pagon RA, Bird TD, Dolan CR, et al., eds. GeneReviews.

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