Sturge-Weber syndrome (SWS) is a rare, non-inherited neurocutaneous disorder, affecting approximately one in 50,000 newborns. This congenital condition is characterized by the abnormal development of small blood vessels in the brain, skin, and eyes. These vascular irregularities lead to a range of symptoms that vary significantly in severity. Early diagnosis and continuous management are important for addressing its diverse manifestations.
The Underlying Cause and Classification
Sturge-Weber syndrome results from a sporadic, somatic (non-inherited) activating mutation in the GNAQ gene, occurring very early in fetal development. This gene provides instructions for making a protein that regulates blood vessel growth and function via cell signaling pathways.
The specific mutation in the GNAQ gene leads to over-activity in the affected cells, causing the abnormal overgrowth of blood vessels observed in the skin, brain, and eyes. The condition is classified into three main types based on which organ systems are involved. Type I is the most common form, involving both facial and leptomeningeal (brain) angiomas, and may also include glaucoma.
Type II involves a facial angioma and the potential for glaucoma, but there is no evidence of brain involvement. Type III is the rarest form, characterized by leptomeningeal angioma and neurological symptoms without the visible facial birthmark. The severity of the condition depends on the extent of vascular malformations in these different areas.
Primary Manifestations of Sturge-Weber Syndrome
The characteristic sign of SWS is a Port-Wine Stain (PWS), a flat, red-to-purple birthmark present at birth. This skin manifestation is a capillary malformation caused by an overabundance of dilated blood vessels near the skin’s surface. The birthmark typically appears on the face, often following the distribution of the ophthalmic division of the trigeminal nerve, which covers the forehead and upper eyelid.
Neurological symptoms arise from a leptomeningeal angioma, an abnormal tangle of blood vessels that grows over the surface of the brain, usually on the same side as the facial PWS. This vascular malformation disrupts normal blood flow and oxygen supply to the underlying brain tissue, leading to progressive damage. The compromised blood supply often results in calcification and eventual loss of brain cells, which can be seen on imaging.
The most common neurological symptom is seizures, which often begin in infancy. These seizures can be challenging to control and may lead to a decline in cognitive function and developmental delays. Individuals may also experience weakness or paralysis on one side of the body, known as hemiparesis, typically opposite the side of the facial PWS.
Ocular involvement is also frequent, with approximately 70% of individuals with SWS developing glaucoma. Glaucoma involves increased pressure within the eye, which can damage the optic nerve and cause vision loss. This increased pressure is often due to abnormal blood vessel growth in the eye’s drainage system. The risk of glaucoma is significantly higher when the PWS involves both the upper and lower eyelids.
Diagnosis and Monitoring
Diagnosis is often suspected at birth based on the characteristic facial Port-Wine Stain. Confirmation and assessment of internal involvement rely on specialized imaging techniques and clinical examinations. Brain imaging is necessary to detect the leptomeningeal angioma and its effects.
Magnetic Resonance Imaging (MRI) is the preferred method for visualizing the angioma and assessing brain changes like atrophy and calcification. Contrast-enhanced MRI highlights abnormal blood vessel growth on the brain’s surface. Computed Tomography (CT) scans effectively detect characteristic brain calcifications, which often appear in a double-lined pattern known as the “tram-track sign.”
A comprehensive ophthalmologic examination is mandatory to screen for glaucoma and other eye complications. This exam includes measuring intraocular pressure to detect early signs of glaucoma. Regular electroencephalogram (EEG) monitoring may also detect subclinical seizure activity. Continuous monitoring is important because brain involvement can progress even without overt symptoms.
Comprehensive Management Strategies
Management of Sturge-Weber syndrome is a lifelong process focused on controlling symptoms and minimizing complications, as there is no cure for the underlying condition. Care coordination requires a multidisciplinary team, including neurologists, ophthalmologists, and dermatologists. Treatment for the Port-Wine Stain involves dermatological intervention to lighten the lesion and improve its appearance.
Pulsed dye laser therapy is the standard treatment for the PWS. It works by selectively targeting and destroying excess blood vessels without significantly damaging the surrounding skin. Multiple treatment sessions are required, and treatment often begins in infancy for the best results and to help prevent soft-tissue overgrowth.
Neurological management centers on preventing and controlling seizures, typically accomplished with anticonvulsant medications. The choice of anti-epileptic drugs is tailored to the individual’s specific seizure type. For severe, drug-resistant seizures that impair development, a neurosurgical procedure like a hemispherectomy may be considered to remove the affected side of the brain.
Physical, occupational, and speech therapies are employed to address developmental delays and muscle weakness. Managing ocular complications, primarily glaucoma, is a high priority to preserve vision. Glaucoma is initially treated with medicated eye drops or oral medications to reduce intraocular pressure by decreasing fluid production. If medication fails, surgical procedures, such as goniotomy or trabeculotomy, are often needed to improve the eye’s fluid drainage.