Sturge-Weber syndrome (SWS) is a rare birth defect of neurocutaneous system, which is characterized by malformation of either facial capillary, cerebral and/or ocular ipsilateral vascular system, thereby resulting in ocular and neurological disorder.
A birthmark usually in the face called port-wine mark or nevus flammeus is the most observable early symptom . The appearance of the birthmark are of different colors (pink, red or dark purple) and sizes. Most often, one of the eyelids are affected and/or one of the frontal part of the head, and less commonly in both sides of the face. Sometimes, this discoloration may be seen covering a half of the face, or extend slightly across the plane of the face. Also, part of the trunk or arms may be affected. Port-wine birthmark associated with SWS results from increased plexus of capillaries beneath the skin surface in the arrangement of trigeminal nerve. Capillaries are network of small blood vessels that connect arteries or veins and are involved in the exchange of blood nutrients including oxygen within cells and tissue. Untreated port-wine birthmarks becomes more thickened and deepened in color with age, sometimes develop into blood blisters (blebs), which could cause spontaneously bleeding (blebbing).
Patients with SWS usually present with varying forms of neurological abnormalities , the extent of which differs from patient to patient. Neurological symptoms result from abnormal development of blood vessels in the brain (a condition called leptomeningeal angiomas). Common symptoms include seizures, which often starts during infancy or childhood. Like the port-wine birthmark, the seizures may affect the different or all part of body side.
Other symptoms include, headaches, visual field defects particularly vision impairment in either one or both eyes (a condition called hemaniopsia), stroke or stroke-like episodes (transient ischemic attacks). Also, a noticeable behavioral problems which include, attention deficit disorder, psychological disorders, and poor social skills are observed in some of the affected children, particularly those with repeated seizures and reduced cognitive function.
Other eye defects commonly associated with SWS include, angiomas of the conjunctiva, blood vessel and choroid between the sclera, retina, and cornea. The eye shows feature of double color (e.g. a brown or blue). Also, there could be abnormal accumulation of fluid in the eye resulting in enlargement of the fibrous coat of the eyeball (condition known as hydrophthalmos), optic atrophy, retinal detachment, angioid streak, and/or cortical blindness. Most patient that develop neurological defect without port-wine birthmark manifestation generally do not show signs of eye problems.
Apart from the general clinical examination of patient for signs and symptoms of SWS, other investigation historically used in establishing diagnosis include  ,
The main diagnostic challenge is the differential test to identify a child with only facial port-wine birthmark presentation from others with brain and/or eye associated with SWS. Clinical conditions such as megalencephaly-capillary malformation-polymicrogyria (MCAP) and Klippel-Trénaunay syndromes (KTS) may share similar features as SWS .
Recent report suggested that prenatal diagnosis is possible using ultrasound or MRI which may reveal hemispheric changes (unilateral gyriform calcification or focal atrophy) in white matter of the brain.
Treatment of Sturge-Weber syndrome include;
Treatment of seizures in SWS cases usually involves an anti-convulsant medications, the efficacy of which varies from one to another. Some patient may not respond to this medications, particularly in cases of refractory seizures despite the intense regimen. Refractory seizures cases, glaucoma, and other disorders associated with SWS including scoliosis , are managed by surgical techniques. The surgical procedures may include, hemispherectomy, vagal nerve stimulation (VNS) or focal cortical resection.
Laser therapy is an effective procedure, which can be used to lighten or erase body port-wine birthmark even in 4- weeks old infants. However, this birthmarks may reoccur or become more darker after the initial treatment, which may therefore require multiple therapy. Port-wine stain birthmark are different either in sizes, distribution or intensity in the body, therefore effective therapy in managing patient may vary depending on the feature of the birthmark. This indicates that different laser technique may be used for the affected body parts. The most commonly known technique for treating port wine stain birthmark associated with SWS is pulse dye laser therapy.
Propranolol, verapamil and prophylactic drugs are often recommended for the treatment of ordinary headache and migrane. Also, some anti-seizure drugs (e.g gabapentin, topiramate, or valproic acid) may be effective in treating migraines or headaches.
Conventional drug treatment of glaucoma associated with SWS are usually ineffective, therefore surgical therapy are considered to be the major method of managing this condition by most opthalmologist .
Common clinical manifestations associated with neurological and developmental morbidities in SWS include, seizures, general body weakness, strokes and headache. Some patient may have physical or mental retardation and hemianopsia.
Age is an important factor in the development or onset of seizure and a determinant of the level of neurologic involvement. Neurologic disorder increases with bilateral port wine stain. Patients may also experience severe eye complications such as refractory seizures, visual loss or blindness due to glaucoma. Some may have cosmetic deformities and other soft-tissue diseases.
Glaucoma develops in 30-71% of patients diagnosed with Sturge-Weber syndrome. The morbidity often seen in SWS due to glaucoma results from early onset of the condition and its resistance to conventional forms of therapy.
SWS results from genetic mutation in a gene called GNAQ . This mutation is somatic in nature since it develops following fertilization of the embryo (mutation of GNAQ in SWS occur in early embryonic stage). Somatic mutation affects all body cell other than the sex cells (i.e sperm and egg cells). This result in different cells carrying varying copies of normal and mutated gene, (mosaic mutation pattern). This genetic pattern is one of the causes of variation in the symptoms of SWS, due to the difference in the number and types of affected cell. Somatic mutations are not hereditically transmitted, therefore not transferable to children. Some studies suggested that somatic mutations involving GNAQ gene occur rarely without any underlying cause.
Genes encodes information for synthesis of protein that are important in various body activities. When genetic mutation occurs, the synthesized protein product may be reduced, inactive or absent. Depending on the affected protein, different organs in the body may be affected. GNAQ gene synthesizes a protein called Gaq that is vital in cell processes, which include control of blood vessel. The underlying factors causing alteration in Gaq protein among SWS patient is not well understood. Further studies are important to evaluate the major mechanism resulting varying symptoms associated with SWS.
As previously stated, SWS symptoms may be due to altered growth or proliferation of some specific blood vessels with secondary effects in the affected tissue. These effects include shortage of oxygen (hypoxia), ischemia and venous obstruction. Also,there may be thrombosis, infarction due to shortage of oxygen in the affected tissue. Brain calcification is also a common feature of the disease.
SWS is an uncommon disorder that usually occur at a rate of about 1 in every 50,000 individuals . There are no racial differences in the incidence of the disease and are sporadically inherited. Generally, this disorder can be diagnosed at birth or early in infancy based on clinical signs and symptoms. However, morbidity which arises from complications and secondary changes persist throughout lifetime.
SWS result from defect in the embyonal blood vessels coupled with the secondary effects on the associated brain tissue. In the cephalic end of the neural tube, plexus of blood vessels develops below ectoderm which later transforms into the facial skin. In a normal process, vascular plexus develops in the sixth week during gestational period and regresses in the ninth week. Alteration in this normal regression process leads to the formation of residual vascular tissue, which transforms into a congenital malformation such as leptomeningeal angiomatosis of the face and the ipsilateral eye.
SWS may cause neurological dysfunction due to the secondary effects on local brain tissue. This include  :
The disease development is progressive  , with neurological manifestation. A condition known as "vascular steal phenomenon" can develop at the angioma site, causing cortical ischemia. Complications such as seizures (e.g status epilepticus, intractable and recurrent seizures) and continuous vascular events may worsening the steal condition, with rapid increase in the development of cortical ischemia. This may result into progressive brain calcification, gliosis, or atrophy of the brain tissue, which may further increases the episode of seizures and neurologic dysfunction  .
Ocular manifestations such as buphthalmos and glaucoma usually occur as a secondary effect of an increased IOP with acute-angle obstruction of the eye, raised episcleral venous pressure, and increased release of aqueous fluid.
Currently, there is no known method to control or prevent the disease.
Features of sturge-weber syndrome include seizure, glaucoma, leptomeningeal angiomatosis of the lobes (particularly parieto-occipital lobes), vascular malformations of the intracranium and face. Ischemia associated with leptomeningeal angiomastosis is commonly observed, which often result from stasis causing necrosis and laminar calcification. There is variation in the disease development with some children presenting symptoms such as intractable seizures, frequent stroke-like episodes, and mental retardation .
SWS are classified into three major types:
Sturge-Weber syndrome is an uncommon birth defect with varying clinical implications. Children born with this condition usually have distinct birthmark called port-wine stain particularly on their face with sometimes nervous system problems.
There is no known cause and any record of genetic transmission of Sturge-Weber syndrome.
Clinical examination of suspected children with birthmark feature by doctor. Other special test may be requested to guide the diagnosis. This include, magnetic resonance imaging (MRI), skull x-ray and angiography. Neurological examination may also be required to determine the neurological involvement.
Treatment of SWS focuses on the observed symptoms.
AuShirley M, Tang H, Gallione C, et al. Sturge-Weber syndrome and port-wine stains caused by somatic mutation in GNAQ. N Engl J Med. 2013; 368(21):1971.