Phakomatoses are a group of neurocutaneous disorders characterised by involvement of structures that arise from the embryonic ectoderm (thus central nervous system, skin and eyes). Other organs may also be involved

Epidemiology

The disease is rare with an estimated prevalance of 1 : 35000 - 50000.

Genetics

The disease carries an autosomal dominant inheritance with high expression and variable penetrance. Classically results from an inactivation of a tumour suppression gene located on chromosome 3p25.5. However no mutation identified in up to 30% of cases.

Radiographic features

Please refer to articles on individual lesions for specific imaging characteristics

Treatment and prognosis

Most lesions with vHL are treatable and screening is recommended (some advocate routine screening starting in adolescence.

Sturge-Weber syndrome or encephalotrigeminal angiomatosis is a phakomatosis. It is characterised by facial port wine stains and pial angiomas.

Demographics and clinical presentation

The diagnosis is usually obvious on account of a congenital facial cutaneous haemangioma (also known as port wine stain or facial naevus flammeus). This feature is almost always present and usually involves the ophthalmic division (V1) of the trigeminal nerve ⁴. Only rarely (~ 5%) is intracranial involvement present without associated cutaneous naevus^1-2. In the majority of cases (72%) the naevus is unilateral and ipsilateral to the intracranial abnormality. 

The most common clinical manifestation is with childhood seizures, present in 71-89% of cases ² that are often refractory to medical therapy ¹. These usually begin in the first few years of life and are often associated with developmental delay and hemispheric symptoms including hemiplegia / hemiparesis and / or hemianopsia.

Approximately a third of patients have choroidal or scleral angiomatous involvement, which may be complicated with retinal detachment, buphthalmos or glaucoma ¹.