What is tuberous sclerosis?
Tuberous sclerosis or tuberous sclerosis complex (TSC) is a genetic disorder that is characterised by hamartomas in many organs, but particularly the skin, brain, eye, kidney and heart. Hamartomas are non-cancerous malformations composed of overgrowth of the cells and tissues that normally occur in the affected area and include naevi (birthmarks). Tuberous sclerosis is also known as epiloia.
Skin lesions, epileptic seizures and developmental delay/behavioural problems are the main features of tuberous sclerosis complex. However, individuals with the condition may be affected in many different ways and with differing degrees of severity. Some patients may have very few or no symptoms at all, whilst others may be severely affected with a multitude of symptoms.
What causes tuberous sclerosis and who gets it?
Tuberous sclerosis is a genetic disorder due to mutation in one of two genes:
- TSC1, which produces a protein called hamartin (10–30% of cases)
- TSC2, which produces a protein called tuberin
About one third of all cases of tuberous sclerosis are inherited from an affected parent. All other cases are due to sporadic new mutations occurring in the early stages of life, most often mutations of TSC2.
People of all races and sex may be affected. The condition may become apparent any time from infancy to adulthood but usually occurs between 2-6 years of age.
What are the skin signs of tuberous sclerosis complex?
Skin lesions are found in 60-70% of cases of tuberous sclerosis.
|Ovoid or ash leaf-shaped white macules||
Other organ involvement
Epilepsy is present in about 70% of patients with tuberous sclerosis.
- Usually begins in infancy or early childhood and may precede appearance of skin lesions by years
- The greater the number of tumours (cortical tubers) in the brain, the greater the severity of seizures.
Developmental delay and behavioural problems may also occur. Symptoms include mild to severe mental retardation, autism, attention deficit disorder (ADD), anxiety, depression, paranoia and schizophrenia.
Other signs and symptoms of tuberous sclerosis include:
- Eye involvement: white spots on the iris and white lumps on the retina
- Heart, gastrointestinal and kidney tumours
- Lung changes
What treatment is available?
Tuberous sclerosis is a multisystem disorder so treatment from a team of specialist doctors is usually necessary.
Experimentally, the topical mTOR inhibitors sirolimus (rapamycin) have proved helpful in reducing angiofibromas in pilot studies involving a few patients. It appears to work best in younger children. One study has reported improvement in hypopigmented macules.
- OMIM – Online Mendelian Inheritance in Man (search term Tuberous sclerosis)
- Book: Textbook of Dermatology. Ed Rook A, Wilkinson DS, Ebling FJB, Champion RH, Burton JL. Fourth edition. Blackwell Scientific Publications.
- Tuberous Sclerosis Complex – GeneTests GeneReviews
- Schwartz RA, Fernandez G, Kotulska K, Jozwiak S. Tuberous sclerosis complex: Advances in diagnosis, genetics, and management. J Am Acad Dermatol 2007;57:189-202. Medline
- Foster RS, Bint LJ, Halbert AR. Topical 0.1% rapamycin for angiofibromas in paediatric patients with tuberous sclerosis: A pilot study of four patients. Australas J Dermatol. 2012 Feb;53(1):52-6. doi: 10.1111/j.1440-0960.2011.00837.x. Epub 2011 Dec 29.
- Wataya-Kaneda M, Tanaka M, Yang L, et al. Clinical and Histologic Analysis of the Efficacy of Topical Rapamycin Therapy Against Hypomelanotic Macules in Tuberous Sclerosis Complex. JAMA Dermatol. 2015;151(7):722-730.
On DermNet NZ:
- Tuberous sclerosis complex US National Library of Medicine Genetics Home Reference
- Dermatologic Manifestations of Tuberous Sclerosis – Medscape Reference
- Tuberous Sclerosis Complex – GeneReviews®
- Tuberous Sclerosis 1 #191100 – OMIM
- Tuberous Sclerosis 2 #613254 – OMIM
- Tuberous Sclerosis Complex New Zealand
- Tuberous Sclerosis Australia
- Tuberous Sclerosis Alliance
- Tuberous Sclerosis Association UK
See the DermNet NZ bookstore