Tuberose sclerosis - Hereditary and congenital disorders

Tuberose sclerosis

Definition

Rare autosomal dominant phacomatosis (hereditary diseases characterised by hamartomas). Also known as tuberous sclerosis.

Incidence

1–5 per 10,000 live births.

Aetiology/pathophysiology

Autosomal dominant inherited condition – two different loci have been found, TSC1 gene one on chromosome 9 which codes for hamartin and the TSC2 gene on chromosome 16 which codes for tuberin – both are tumour suppressor genes. There is incomplete genetic expression and hence variable severity and a variable family history. Hamartomas appear in many different organs, including the brain which shows characteristic nodules (tubers) on the walls of the ventricles.

Clinical features

Skin manifestations: depigmented patches which fluoresce with Wood’s light, shagreen patches – rough-ened patches of skin, amelanotic naevi, angiofibromas (adenoma sebaceum) in butterfly malar distribution occurring after the age of 3.

Neurological manifestations: infantile spasms, mental retardation, partial seizures.

A minority of patients develop cardiac or renal tumours and polycystic kidneys.

Complications

Cardiac failure, arrhythmias including Wolf Parkinson White syndrome, renal cell carcinoma in less than 1%, liver angiomas (25% of patients but rarely symptomatic)

Investigations

Multiple intracranial nodules can be seen on CT or MRI, after 1 year these calcify and can be seen on skull X ray. Renal ultrasound and echocardiogram may be required.

Management

Annual review is recommended to assess seizure control and screen for development of new symptoms or complications. Skin lesions may respond to argon lasers and pulsed dye lasers (vascular lesions) or CO2 lasers (fibrous lesions).