What is Sturge Weber Syndrome?
Sturge Weber syndrome (also known as Sturge Weber disease or encephalotrigeminal angiomatosis) is a rare disorder present at birth. This disease is usually characterized by the presence of so called port wine stain birthmark on the face, eye and neurological abnormalities. In some cases the birthmark can be absent. Although the symptoms are presented at birth, this disease does not run in the family. The severity of the syndrome varies dramatically from one person to another. This disease belongs to a group of neuro-cutaneous disorders [1,2].
There is an excessive growth of blood vessels on the surface of the brain. It causes disturbances in normal brain function. One of the most common manifestations of brain involvement is seizures. The seizures can involve both sides of the body, but usually they are on the opposite side as the birthmark. The seizures usually begin in infancy or early childhood and they are likely to worsen with age.
Affected individuals may also experience paresis on one side of the body (hemiparesis). In some cases, normal physical and intellectual development is impaired. Hemiparesis is also associated with transient ischemic attacks and stroke. Migraine can also be a normal occurrence for those affected with Sturge Weber syndrome [1,3].
Port wine stain in Sturge Weber syndrome is an area of purple or dark red skin, usually involving eyelid and forehead. The stain usually has well-defined borders. The stain is usually present on the face, but any part of the body can be affected. The color and size of it can differ. For persons with darker skin pigmentation the stain can be difficult to recognize. At birth, the surface is usually flat, but it can become more pronounced after a while . This birthmark is caused by overabundance of small blood vessels-capillaries beneath the skin surface It is distributed in the innervation zone of trigeminal nerve. If port wine stain is left untreated, it can cause skin ulcers or burst spontaneously. It also can cause social predicaments for the patient
The most common ocular manifestation of Sturge Weber syndrome is glaucoma. Glaucoma is characterized by increased intraocular pressure. In this syndrome usually one eye is affected on the same side as the port wine birthmark. The blood vessels of the eye are damaged; therefore the normal circulation of intra ocular liquid is disrupted. Since intraocular liquid is not reabsorbed, it creates a pressure buildup. Glaucoma results in progressive vision loss, because of the damage caused on optic nerve. The eye can also become enlarged and bulge.
Other ocular manifestations are:
- Hemangioma of the eyelid, conjunctiva and episclera
- Iris heterochromia
- Choroidal hemangioma
- Tomato-catsup color of the ocular fundus
Sturge Weber syndrome was classified into 3 types by Dr. Steve Roach in 1992:
Most common type. Presents with skin and brain (leptomeningeal) vascular malformations (angiomas). This type also includes eye abnormalities, like glaucoma. In the first year of life patients experience seizures because of the brain involvement. First year of life is also when the eye abnormalities are usually diagnosed. Mental and physical development of the patient might be impaired depending of the degree of vascular malformations in the brain.
Initially presents with the port wine stain birthmark, but no other symptoms are present. Brain tissue is not involved in type II. During the life of patient symptoms related to this disease might occur, like glaucoma, cerebral blood flow disturbances.
In this case the brain leptoangioma is present with no face involvement or glaucoma .
Sturge Weber syndrome is a genetic condition. It is caused by mutation in the somatic GNAQ gene (guanine nucleotide binding protein, Q polypeptide), which is associated with platelet activation and aggregation problems. The mutation occurs after fertilization in early stages of embryogenesis. The mutation can occur in any cell of the body in various amounts. The severity of symptoms is partially due to the ratio of abnormal cells versus healthy cells. The mutations in this gene occur randomly and a cause for it has not been found. The precise mechanism of how the mutated gene functions is not yet understood. It is only known that the mutated gene causes abnormal development, growth and proliferation of blood vessels [6,7].
In case this syndrome is suspected at birth, possible glaucoma has to be diagnosed. In infants, glaucoma can progress rapidly; therefore it is important to take measures to reduce the process. Next steps include variety of imaging studies:
- Radiography of the skull can present
- Cortical calcifications
- No filling in dural sinuses
- Angiography can present abnormal blood vessels and drainage from the veins
To diagnose this syndrome, magnetic resonance imaging with gadolinium is used. Gadolinium is contrast dye and helps to produce a more detailed picture of the blood vessels and brain tissue. This disease can present with cortical atrophy, hyperperfusion and accelerated myelination .
Computed tomography reveals cross sectional images of certain brain structures. In case of this syndrome following signs can be found: enlarged choroid plexus (a blood vessel formation in the brain), venous sinus occlusion, calcifications .
The treatment includes various procedures and medications to relieve the symptoms:
- Anticonvulsants to control seizure activity
- Pain medication in case of headaches
- Glaucoma treatment can include medication. Unfortunately medications usually fail with time therefore surgery is suggested.
- Laser therapy to reduce the port wine stains
In case of severe epileptic activity brain surgery can be done. Hemispherectomy is performed if a large, unilateral epileptogenic region has been found. In case the region causing epileptic seizures is smaller, cortical resection can be performed [1,2,7].
The life expectancy of Sturge Weber syndrome directly correlates to the extent of angiomas in the brain. Poor prognostic factors are early seizure onset, extensive brain angioma, permanent motor deficit, progressive neurological damage and progressive atrophy. Life expectancy is usually normal, but it depends on how well the symptoms are managed .
- http://www.genecards.org/cgi-bin/carddisp.pl?gene=GNAQ about the gene