Overview
Epidemiology
The incidence is 1 in 50,000 live births.
Etiology
- Congenital but not inherited
- Sporadic mutation with no known cause
- Somatic mosaicism of the GNAQ gene → not passed onto offspring
Pathophysiology
- GNAQ gene: encodes G-alpha-q, a guanine nucleotide-binding protein → regulates intracellular signaling pathways
- Mutation results in irregular growth of the endothelial cells.
- Presents as capillary-venous malformation, especially in the dermal and leptomeningeal regions
Clinical Presentation
Symptoms are usually due to the effect of capillary-venous malformation within the brain, skin, and eye. Not all symptoms have to be present in an individual for them to be diagnosed with SWS, and some symptoms may develop later in life.
Dermatological
Port-wine stain (PWS):
- A nevus flammeus
- Present from birth
- Distribution:
- Facial: ophthalmic and maxillary branches of the trigeminal nerve
- Trunk
- Arm
- Light pink to deep red
Port-wine stain (PWS):
Image: “Diffuse nevus flammeus involving the left upper eyelid and forehead associated with Sturge-Weber syndrome” by Kubicka-Trząska A, Kobylarz J, Romanowska-Dixon B. License: CC BY 3.0
Diffuse nevus flammeus involving the left upper eyelid and forehead
Port-wine stain (PWS):
Image: “Bilateral port-wine stain over face” by Patil B, Sinha G, Nayak B, Sharma R, Kumari S, Dada T. License: CC BY 3.0
Bilateral nevus flammeus over the face
Neurological
- Leptomeningeal vascular malformation, also called leptomeningeal angioma
- Benign tumor of the arachnoid and pia mater
- Ipsilateral to PWS
- Mainly in parietal and occipital lobes
- Leads to atrophy and calcifications in the cerebral cortex below the tumor, causing:
- Seizures:
- Early onset (by 6 months)
- Usually the presenting complaint
- Focal seizures
- Hemiparesis/hemianopia:
- Stroke-like symptoms
- Transient
- Intellectual disability, learning difficulties
- Mood disorders
- Seizures:
Ophthalmological
- Episcleral angioma → glaucoma (early onset)
- Homonymous hemianopia
- Strabismus
- Increased tearing
- Choroidal hemangioma
Endocrine
- Reduced growth hormone (GH) → short stature
- Central hypothyroidism
Mnemonic
An easy way to remember is by using the mnemonic STURGE:
- Seizures
- Tram-track-like calcification
- Unilateral PWS
- Retardation
- Glaucoma
- Epilepsy
Diagnosis and Management
Diagnosis
- Neuroimaging:
- MRI with contrast: enhances leptomeningeal angiomas
- CT: tram-track-like calcification
- Done immediately if patient presents with neurological symptoms
- Done after 1 year of age in patients with PWS
- Eye exam, measurement of intraocular pressure (IOP)
- EEG → to assess seizure activity
- Confirmation: genetic testing for mutations in GNAQ
Epilepsy associated with Sturge-Weber syndrome (SWS): Sturge-Weber syndrome in a 14-year-old boy with multiple epileptic foci in the right cerebral hemisphere and chronic partial epilepsy
A: axial T2-weighted image showing right cerebral hemiatrophy (white arrows)
B: axial T1-weighted sequence after gadolinium injection, demonstrating leptomeningeal enhancement of the frontoparietal region (white arrows)
C: White arrows point to cortical calcification in the frontal lobe, appearing as signal voids from subjected weighted images.
Management
- Symptom treatment:
- PWS: pulsed dye laser therapy
- Seizures:
- Anticonvulsants (carbamazepine)
- Hemispherectomy in refractory cases
- Glaucoma: topical or surgical management
- Prevention:
- Low-dose aspirin (likely reduces the risk of cerebral ischemic events and seizures)
- Regular ophthalmological examination to monitor IOP
Prognosis
- Determined by extent of lesion and age of onset for seizures
- Neurological function likely deteriorates with age, impairing daily function.
Differential Diagnosis
Klippel-Trenaunay syndrome (KTS): a rare congenital and sporadic disease that results in vascular malformation similar to SWS. In contrast to SWS, neurological and ophthalmological symptoms are rare and PWSs are more commonly noted on the limbs. Bone and muscle involvement results in hypertrophy of limbs. Treatment consists of surgical debulking or sclerotherapy of the malformed vessels.
References
- NORD (National Organization for Rare Disorders). (2017). Sturge Weber syndrome. Retrieved August 17, 2021, from https://rarediseases.org/rare-diseases/sturge-weber-syndrome/
- Shirley, MD, Tang, H, Gallione, CJ, et al. (2013). Sturge-Weber syndrome and port-wine stains caused by somatic mutation in GNAQ. N Engl J Med. 368(21), 1971–9. https://doi.org/10.1056/NEJMoa1213507
- Comi, AM. (2011). Presentation, diagnosis, pathophysiology, and treatment of the neurological features of Sturge-Weber syndrome. Neurologist. 17(4), 179–184. https://doi.org/10.1097/NRL.0b013e318220c5b6
- Sujansky, E, & Conradi, S. (1995). Sturge-Weber syndrome: Age of onset of seizures and glaucoma and the prognosis for affected children. J Child Neurol. 10(1), 49–58. https://doi.org/10.1177/088307389501000113
- Patterson, MC. (2021). Sturge-Weber syndrome. UpToDate. Retrieved August 18, 2021, from https://www.uptodate.com/contents/sturge-weber-syndrome
