What are the clinical features of Sturge-Weber syndrome?

Sturge-Weber Syndrome: Clinical Features

Sturge-Weber syndrome (SWS) is characterized by the classic triad of facial port-wine birthmark (capillary malformation), leptomeningeal vascular malformation, and ocular involvement, though diagnosis requires only two of these three features. 1

Cutaneous Manifestations

The facial port-wine birthmark is present in approximately 94.5% of cases 2:

• Unilateral in 63.5% of patients
• Bilateral in 31%
• Notably, 5.5% of patients with confirmed leptomeningeal angiomas have no facial birthmark 2
• Typically involves the head/neck region, particularly the upper eyelid
• All patients with upper eyelid involvement have ipsilateral choroid-retinal angiomas 2

Critical caveat: The size of the facial birthmark does NOT correlate with severity of brain involvement 2. Additionally, 41% of patients with bilateral facial birthmarks have only unilateral brain involvement 2.

Neurological Features

Seizures (Most Common Presentation)

• Occur in 85.5-100% of patients 3, 2
• Mean onset at 6.6 months of age 4
• Partial seizures (simple or complex) are most frequent (62%) 3
• Status epilepticus develops in 64% 4
• Drug-resistant epilepsy occurs in 27-42.5% of cases 3, 4

Early seizure onset (particularly before 2 months) predicts worse prognosis, especially with bilateral leptomeningeal involvement 4.

Other Neurological Manifestations

• Hemiparesis: 39% 3
• Stroke-like episodes: 23-64% 3, 4
• Recurrent headaches (migraine-like): 36-39% 3, 4
• Intellectual disability/psychomotor retardation: 46-64% 3, 2
  • Only 36% have IQ >70 2
  • Bilateral brain involvement significantly worsens cognitive outcomes 4

Ocular Manifestations

Ocular disease occurs in 77% of patients 3:

• Glaucoma: 46% (most common and serious complication) 3
• Choroidal hemangioma: 23-87.5% (detection rate varies by imaging modality) 3, 5
• Strabismus: 23% 3
• Heterochromia of the iris
• Visual field defects 6

Monitoring recommendation: Ophthalmological examination every 3 months during the first year, then yearly 7.

Brain Imaging Findings

Leptomeningeal Angiomatosis (Pathognomonic)

• Present in 100% of confirmed SWS cases 3
• Unilateral in 86%: right hemisphere (46%), left hemisphere (38%)
• Bilateral in 13-15% 3, 4
• Infratentoral extension in 23% (associated with worse intellectual outcomes) 4

Progressive Changes

• Leptomeningeal calcifications visible in 85% on MRI 3
• Increased calcification over time in 70% 3
• Choroid plexus thickening on MRI has high sensitivity/specificity for early detection 7

Important: Cerebral lesions progress during early childhood but stabilize later 2.

Genetic Basis

• GNAQ gene mutation (R183Q): most common somatic mutation 8
• GNA11 and GNB2 mutations: less common variants 8
• Postzygotic, somatic, gain-of-function variants (not inherited) 7

Prognostic Indicators for Poor Outcome

The following predict severe disease 2, 4:

1. Early seizure onset (especially <2 months)
2. Poor response to initial antiepileptic treatment
3. Bilateral cerebral involvement
4. Bilateral leptomeningeal angioma with early calcifications
5. Infratentorial extension

Additional Features

• Endocrine disorders: growth hormone deficiency, central hypothyroidism 6
• Other skin disorders: hemilateral involvement, cutis marmorata (23%) 3
• Facial asymmetry and gingival hyperplasia 1

Key clinical pearl: The absence of pathologic MRI findings effectively rules out neurological involvement, allowing for periodic observation rather than aggressive monitoring 7.