Chapter 207: Sturge-Weber Syndrome

Patient Story

A 3-year-old girl is referred to a pediatric neurologist because of a history of developmental delay and focal seizures since birth that are no longer being well controlled with two antiseizure medications. On physical exam, the neurologist notes a large bilateral port-wine stain on the face (Figure 207-1). The neurologist suspects that the child has Sturge-Weber syndrome and orders brain imaging and an ophthalmologic exam. The MRI reveals leptomeningeal angiomas and the ophthalmologist diagnoses glaucoma. The diagnosis of Sturge-Weber syndrome is confirmed and education is provided to the parents on this condition. The child’s anti-epileptic medications are maximized and her glaucoma is treated by the ophthalmologist.

Introduction

Sturge-Weber syndrome (SWS) is a sporadic congenital neurocutaneous syndrome that is characterized by facial capillary malformation known as a port-wine stain, ocular abnormalities including glaucoma and choroidal hemangioma, and leptomeningeal angiomas. Seizures, developmental delay and glaucoma comprise the major clinical features. SWS is associated with mutations in the GNAQ gene.

Synonyms

Encephalotrigeminal angiomatosis and encephalofacial angiomatosis.

Port-wine stains are also called nevus flammeus.

Epidemiology

• SWS occur sporadically at a rate of 1 per 20,000 to 50,000 newborns and in equal frequency in both genders.¹

Etiology and Pathophysiology

• SWS is caused by somatic activating mutations in GNAQ gene, as confirmed by a whole-genome sequencing study that examined skin and brain tissue samples.¹

• GNAQ encodes for G-alpha-q, a G-protein alpha subunit that acts as a mediator between G-protein coupled receptors and downstream signaling molecules.

• In fetal ectodermal tissue, this mutation is thought to cause inappropriate maturation of capillaries, thus leading to capillary malformations.¹ The port-wine stain is due to a dilation of capillaries and venous blood vessels in the dermis rather than a proliferation of the capillaries.²

Diagnosis

Clinical Features

• Physical manifestations of SWS can be divided into cutaneous, ocular, and neurologic. The diagnosis is usually made based on the presence of the facial capillary malformations and leptomeningeal angiomas.²

• Cutaneous:

  • The most obvious sign of SWS is the facial capillary malformation, known as a port-wine stain, due to its color (Figures 207-1 to 207-3).

  • Note that a capillary malformation is not the same as a cutaneous hemangioma even though these are often confused as the same entity. While there are ocular and CNS angiomas ...