Neurocutaneous syndrome – Sturge Weber syndrome (SWS)

Written by Wesam Tamimi, M.D.

Keywords: Sturge-Weber Syndrome, port-wine stain, leptomeningeal angiomas, seizures, glaucoma, neurological abnormalities, pediatrics, rare genetic disorders.

Overview

Sturge-Weber syndrome (SWS) is a rare, congenital neurocutaneous disorder characterized by a distinctive facial birthmark known as a port-wine stain, along with neurological, ocular, and dermatological manifestations. The syndrome results from a somatic mutation in the GNAQ gene, leading to abnormal blood vessel formation in the skin, brain, and eyes. The severity of symptoms varies depending on the extent of involvement, and early diagnosis is essential for managing associated complications.

Buzzwords Scenario: A newborn presents with a port-wine stain on the left side of the face, along with episodes of focal seizures. MRI findings reveal leptomeningeal angiomas on the ipsilateral side.

Definition

Sturge-Weber syndrome is a congenital disorder that involves a combination of a port-wine stain on the face, leptomeningeal angiomas (abnormal blood vessels on the brain surface), and ocular issues such as glaucoma.

Epidemiology

●      Prevalence: 1 in 20,000-50,000 live births.

Etiology

●       Caused by a somatic single-nucleotide variant in the GNAQ gene.

●       Mosaic pathologic genetic variant found in endothelial cells of SWS brain lesions.

Pathophysiology

●       Port-wine stain (PWS): A vascular malformation of capillaries in the skin, most commonly affecting the face, especially along the trigeminal nerve distribution.

●       Leptomeningeal angiomas: Abnormal blood vessels on the surface of the brain, usually on the same side as the port-wine stain → Low flow in leptomeningeal capillary malformations → chronic hypoxia → cortical atrophy and calcifications in the brain → seizures

●       Ocular glaucoma: Increased intraocular pressure → optic nerve damage, often associated with eye involvement on the side of the port-wine stain.

Clinical Features

Dermatological:

●       Port-wine stain (PWS): A vascular birthmark, most commonly located on the face along the trigeminal nerve distribution. The port-wine stain darkens over time and does not fade naturally.

Neurological:

●       Seizures: Often the first sign of neurological involvement, typically occurring in the first year of life. Seizures are focal in nature and may progress to generalized.

●       Cognitive and developmental delays: Normal in the first year of life but intellectual disability, motor delays, and speech difficulties, develops in 50% of cases especially if brain involvement is severe.

●       Hemiparesis or hemisensory deficits: Depending on the extent of leptomeningeal angiomas, patients may present with weakness or sensory loss on the side of the port-wine stain.

●       Stroke-like episodes: Transient, lasting several days, and are not related to seizures, likely due to thrombosis of cortical veins.

Ocular:

●       Glaucoma: A common complication that presents in the ipsilateral side with eye redness, visual impairment, or a cloudy cornea. Increased intraocular pressure leads to optic nerve damage if not managed early.

Figure 1. Port wine stain seen under the nose and on the right side of the face

ArturroD. (2014, June 15). A new born child with M-CM syndrome [Photograph]. Wikimedia Commons. https://commons.wikimedia.org/wiki/File:A_new_born_child_with_m-cm_syndrome..png

NOTE: Not all port wine stains are associated with Sturge weber syndrome Diagnosis

●       Clinical diagnosis: The characteristic port-wine stain, combined with neurological symptoms (seizures, developmental delay), is suggestive of Sturge-Weber syndrome.

●       Imaging: MRI is the gold standard for detecting leptomeningeal angiomas. It may show cortical atrophy and abnormal blood vessels on the brain surface.

●       Ocular Examination: Regular eye exams are essential to monitor for glaucoma, which can lead to optic nerve damage if untreated.

NOTE: Brain calcifications is best observed on CT scan

ALERT: SWS may overlap with Klippel-Trénaunay syndrome, which involves mixed capillary, venous, or lymphatic malformations affecting bone and muscle in one limb.

Figure 2. CT scan of a child with Sturge weber syndrome with significant subcortical white matter calcifications

Gaillard, F. (n.d.). CT of the brain of a 20-month-old child with Sturge-Weber syndrome [Radiograph]. Wikimedia Commons. https://en.wikipedia.org/wiki/File:Sturge-Weber_CT.jpg

Management

Primarily symptomatic and multidisciplinary.

Goals of treatment:

●       Seizure control.

●       Relief of headaches and prevention of stroke-like episodes.

●       Monitoring and management of glaucoma.

●       Laser therapy for cutaneous capillary malformations (port-wine birthmarks).

Laser therapy: Effective for clearing the PWB, especially when located on the forehead,

and it helps in the psychological trauma.

NOTE: Seizure management

●       Presymptomatic treatment in high-risk infants may help delay or prevent seizures.

●       For well-controlled seizures and normal development:

o   Anticonvulsants and surveillance for complications (e.g., glaucoma, behavioral issues).

●       For refractory seizures, especially in infants under 2 years of age:

o    Consider hemispherectomy or focal disconnections if seizures originate from one hemisphere.

Reference

Pinto, A. L. (2024). Sturge-Weber syndrome. In R. M. Kliegman, J. W. St. Geme III, & N. F. Schor (Eds.), Nelson Textbook of Pediatrics (22nd ed., pp. 3659–3661). Elsevier.