Tuberous sclerosis (TSC) is a genetic neuro-cutaneous disorder characterized by formation of benign tumors, especially affecting the skin and the central nervous system. The tumors are usually either benign hamartias or hamartomas. Only very rarely, are cancerous hamartoblastomas encountered. Dermatological features include the presence of hypomelanotic macules, depigmented spots, ashlead pattern depigmentation, shagreen patches, and/or growth under the nails. Tumors within the brain result in neurological symptoms, including seizures (tonic, clonic, myoclonic, and infantile), behavioral problems, developmental delays, learning disabilities, mental retardation, and features of autism. Behavioral problems, such as attention deficit hyperactivity disorder, aggression, obsessive compulsive disorder, and hyperactivity are fairly common. Tumors may also be seen affecting the kidneys, heart, and lungs. Angiomyolipomas are frequently seen in the kidneys. Cardiac manifestations are in the form of arrythmias, rhabdomyoma, or atrial septal defect. It is estimated that TSC affects about one in 6,000 people.
Diagnosis of TSC is on the basis of the clinical symptoms and features, and on the presence of a family history for this condition. Physical examination, as well as CAT, MRI, and ultrasound scans are utilized for confirming the diagnosis. Genetic testing is also now available for detecting the disease.
Unfortunately, there is no cure for TSC. Symptomatic treatment, however, is available. Seizures are controlled by anti-epileptic medications, and behavioral problems and learning disabilities can be overcome by special schooling and occupational therapies. Skin lesions can be managed with the help of surgical treatment. Prognosis is fairly good for people with mild symptoms. However, in patients with the severe form of the disease, affecting the kidneys and brain, the condition may be fatal.
The TSC genes are responsible for the development of tuberous sclerosis. At least four different genes are recognized: TSC1, TSC2, TSC3, and TSC4. Tuberous Sclerosis 1 is linked to the TSC1 (chromosome 9) gene, which encodes hamartin.