Sturge-Weber syndrome (SWS) is a rare congenital neurocutaneous disorder characterized by facial capillary malformations and/or cerebral and ocular ipsilateral vascular malformations that result in variable degrees of ocular and neurological anomalies.
The birth prevalence in Europe is estimated at around 1/20,000 and 1/50,000.
The facial capillary malformation (classically referred to as angioma) is a port-wine stain (PWS) that is generally present at birth and located on the forehead or upper eyelid on one or both sides of the face. Sometimes, the PWS may also cover the maxillary and mandibular areas of the face and in some cases may extend to the trunk and limbs. Soft tissue and bony hypertrophy can be associated with a developing PWS that can lead to vision, hearing, swallowing, and speaking problems. In rare cases, patients may not present with PWS. Eye involvement can occur at anytime but is generally observed during infancy and young adulthood. More than 50% of patients develop glaucoma on the same side of the face as the PWS that can lead to optic atrophy and blindness. Cerebral vascular malformations are also present. Infants typically present in the first year of life with leptomeningeal angiomatosis, responsible for the occurrence of focal or complex partial seizures, early-handedness, and visual gaze preference. Migraines and stroke-like episodes are also very common. With the progression of the disease, and depending on the severity of seizures, patients may develop hemiparesis, hemiplegia, and variable degrees of intellectual disability. Less common aspects include an increased risk of growth hormone deficiency.
SWS syndrome is caused by a somatic mosaic mutation in GNAQ (9q21) that codes for the protein Gαq which is critical to the intracellular signaling of a large group of G protein coupled receptors important to the function of several growth factors, vasoactive peptides, and neurotransmitters.
Diagnosis is suspected upon clinical examination. Depending on the extent of the birthmark, the risk of SWS in infants with a PWS ranges between 15-40%. Diagnosis is confirmed by imaging techniques (radiography, CT scan or MRI with contrast) showing, as the disease progresses, ipsilateral cerebral hemiatrophy, cortical calcifications delineating the cerebral gyri, and leptomeningeal angiomatosis. Functional cerebral imagining can be useful (e.g. cerebral blood flow measurement, positron emission tomography (PET)).
The main diagnostic concern is separating the child with an isolated facial port-wine birthmark from one with SWS brain and/or eye involvement. The diagnosis of megalencephaly-capillary malformation-polymicrogyria and Klippel-Trénaunay syndromes (see these terms) may also be raised.
According to a recent report, prenatal diagnosis may be suggested by ultrasound or MRI revealing unilateral hemispheric gyriform calcification, focal hemispheric atrophy and white matter changes.
The disease is sporadic.
Laser treatment, usually started in infancy, reduces the progression of the PWS and allows partial, or in rare cases, complete, clearance. Anticonvulsants (e.g. levetiracetam, phenobarbital, oxcarbazepine), often in combination with low-dose aspirin, are used to treat epilepsy. Focal resection or hemispherectomy should be investigated when medical management fails to control the seizures. Therapy with eye drops is used to decrease pressure in the eye. Surgery may be recommended. Frequent ophthalmologic examinations should be carried out in cases with glaucoma. Physiotherapy is required for muscular weakness and functional impairments.
The prognosis depends on the severity of the epileptic crises which may lead to variable degrees of psychomotor regression and intellectual disability.
Last update: March 2014
- Dr Anne COMI
- Dr Jonathan PEVSNER