science

Sturge–Weber syndrome

Sturge–Weber syndrome is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Sturge–Weber syndrome rather than just read about it. In short: Sturge–Weber syndrome, sometimes referred to as encephalotrigeminal angiomatosis, is a rare type of phakomatosis, a congenital disorder that affects the central nervous system, skin, and eyes. It is often associated with port-wine stains of the face.

Key takeaways

Sturge–Weber syndrome belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Sturge–Weber syndrome to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Sturge–Weber syndrome from memory before moving on to harder problems.

Reference excerpt

Sturge–Weber syndrome, sometimes referred to as encephalotrigeminal angiomatosis, is a rare type of phakomatosis, a congenital disorder that affects the central nervous system, skin, and eyes. It is often associated with port-wine stains of the face. Clinical manifestations include glaucoma, choroidal lesions, seizures, intellectual disability, and benign tumors of the blood vessels of the leptomeninges. Sturge–Weber originates from embryonic development, resulting from errors in mesodermal and ectodermal development. Unlike other phakomatoses, Sturge–Weber occurs sporadically (i.e., does not have a hereditary cause). It is caused by a mosaic, somatic activating mutation occurring in the GNAQ gene. Diagnosis is usually done through imaging; findings may include tram track calcifications in the cerebral cortex on a CT scan, angiomatosis of the pia mater, and hemicerebral atrophy. Managing Sturge–Weber focuses on treating the symptoms as they appear. Around 1 in 50,000 newborns are affected by the disease. It was originally described in 1879 by William Allen Sturge.

Signs and symptoms

Sturge–Weber syndrome is usually manifested at birth by a port-wine stain on the forehead and upper eyelid of one side of the face, or the whole face. The birthmark can vary in color from light pink to deep purple and is caused by an overabundance of capillaries around the ophthalmic branch of the trigeminal nerve, just under the surface of the face. There is also malformation of blood vessels in the pia mater overlying the brain on the same side of the head as the birthmark. This causes calcification of tissue and loss of nerve cells in the cerebral cortex. Neurological signs include seizures that begin in infancy and may worsen with age. Convulsions usually happen on the side of the body opposite the birthmark, and vary in severity. There may also be muscle weakness on the side of the body opposite the birthmark. Some children will have developmental delays and cognitive delays; about 50% will have glaucoma (optic neuropathy often associated with increased intraocular pressure), which can be present at birth or develop later. Glaucoma can be expressed as leukocoria, which should suggest further evaluation for retinoblastoma. Increased pressure within the eye can cause the eyeball to enlarge and bulge out of its socket (buphthalmos). Sturge–Weber syndrome rarely affects other body organs.

Cause The blood vessel formations associated with SWS start in the fetal stage. Around the sixth week of development, a network of nerves develops around the area that will become a baby's head. Normally, this network goes away in the ninth week of development. In babies with SWS due to mutation of gene GNAQ, this network of nerves doesn't go away. This reduces the amount of oxygen and blood flowing to the brain, which can affect brain tissue development.

Diagnosis

CT and MRI are most often used to identify intracranial abnormalities. When a child is born with a facial cutaneous vascular malformation covering a portion of the upper or the lower eyelids, imaging should be performed to screen for intracranial leptomeningeal angiomatosis. The haemangioma present on the surface of the brain is in the vast majority of cases on the same side as the birth mark and gradually results in calcification of the underlying brain and atrophy of the affected region.

Classification Sturge–Weber syndrome can be classified into three different types. Type 1 includes facial and leptomeningeal angiomas as well as the possibility of glaucoma or choroidal lesions. Normally, only one side of the brain is affected. This type is the most common. Type 2 involvement includes a facial angioma (port wine stain) with a possibility of glaucoma developing. There is no evidence of brain involvement. Symptoms can show at any time beyond the initial diagnosis of the facial angioma. The symptoms can include glaucoma, cerebral blood flow abnormalities and headaches. More research is needed on this type of Sturge–Weber syndrome. Type 3 has leptomeningeal angioma involvement exclusively. The facial angioma is absent and glaucoma rarely occurs. This type is only diagnosed via brain scan.

Treatment Treatment for Sturge–Weber syndrome is symptomatic. Laser treatment may be used to lighten or remove the birthmark. Anticonvulsant medications may be used to control seizures. Doctors recommend early monitoring for glaucoma, and surgery may be performed on more serious cases. When one side of the brain is affected and anticonvulsants prove ineffective, the standard treatment is neurosurgery to remove or disconnect the affected part of the brain (hemispherectomy). Physical therapy should be considered for infants and children with muscle weakness. Educational therapy is often prescribed for those with intellectual disability or developmental delays, but there is no complete treatment for the delays. Brain surgery involving removing the portion of the brain that is affected by the disorder can be successful in controlling the seizures so that the patient has only a few seizures that are much less intense than pre-surgery. Surgeons may also opt to "switch-off" the affected side of the brain. Latanoprost (Xalatan), a prostaglandin, may significantly reduce IOP (intraocular pressure) in patients with glaucoma associated with Sturge–Weber syndrome. Latanoprost is commercially formulated as an aqueous solution in a concentration of 0.005% preserved with 0.02% benzalkonium chloride (BAC). The recommended dosage of latanoprost is one drop daily in the evening, which permits better diurnal IOP control than does morning instillation. Its effect is independent of ethnicity, gender or age, and it has few to no side effects. Contraindications include a history of cystic macular edema (CME), epiretinal membrane formation, vitreous loss during cataract surgery, history of macular edema associated with branch retinal vein occlusion, history of anterior uveitis, and diabetes mellitus. It is also wise to advise patients that unilateral treatment can result in heterochromia or hypertrichosis that may become cosmetically objectionable.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Sturge–Weber syndrome

Start with the simplest possible case. Write down what Sturge–Weber syndrome claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Sturge–Weber syndrome before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Sturge–Weber syndrome ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Sturge–Weber syndrome

In research: Sturge–Weber syndrome appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Sturge–Weber syndrome in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Sturge–Weber syndrome is common in secondary-school and first-year university syllabi. It links to neighbouring topics Congenital disorders of eye, ear, face and neck, Congenital disorders of nervous system, Genodermatoses, so understanding it makes those chapters shorter.
In everyday life: Look for Sturge–Weber syndrome outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Sturge–Weber syndrome” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Sturge–Weber syndrome in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Sturge–Weber syndrome means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Sturge–Weber syndrome out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Sturge–Weber syndrome in simple terms?

Why does Sturge–Weber syndrome matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Sturge–Weber syndrome?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Sturge–Weber syndrome.