Sturge–Weber syndrome

Sturge–Weber syndrome is a congenital disorder caused by a postzygotic mosaic variant in GNAQ. It is characterized by facial capillary malformations and abnormal vascular tissue in the brain, with possible seizures, stroke-like episodes, and glaucoma.

GNAQ: GNAQ is a gene encoding a signaling protein that helps regulate cellular responses to external signals. Postzygotic activating variants in this gene drive the affected tissues in most cases.
Capillary malformation: A capillary malformation is a congenital low-flow vascular anomaly caused by abnormally formed small blood vessels. The facial and meningeal lesions are distinct manifestations of this vascular anomaly.
Antiseizure medication: Antiseizure medications reduce the frequency or severity of seizures by altering neuronal excitability. Medication is commonly used to manage seizures associated with brain involvement.
Seizure: A seizure is a transient episode of abnormal, excessive, or synchronous neuronal activity in the brain. Seizures are a frequent neurological manifestation of brain vascular involvement.
Isolated port-wine birthmark: An isolated port-wine birthmark is a skin capillary malformation without the characteristic brain involvement of Sturge–Weber syndrome. A facial birthmark alone does not establish that the brain is affected.
Somatic mosaicism: Somatic mosaicism is the presence of genetically distinct cell populations within one individual, arising after fertilization. The mutation occurs after fertilization, so only some cells carry the variant.
Neurocutaneous disorder: A neurocutaneous disorder affects both the nervous system and the skin, often through shared developmental abnormalities. The syndrome is defined by linked skin and nervous-system vascular findings.
Focal cortical resection: Focal cortical resection is surgery that removes a localized area of brain tissue generating seizures. It may be considered when seizures remain severe despite medication.
Stroke-like episode: A stroke-like episode is a transient neurological deterioration resembling stroke without necessarily involving an arterial blockage. These episodes can occur alongside seizures and abnormal brain perfusion.
Klippel–Trenaunay syndrome: Klippel–Trenaunay syndrome is a congenital overgrowth disorder involving capillary malformations, venous or lymphatic abnormalities, and limb asymmetry. Both involve vascular malformations, but Klippel–Trenaunay primarily affects a limb.

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Rasmussen syndromeCompared with: It can cause unilateral seizures and brain atrophy, but has a distinct vascular and congenital basis.