Williams syndrome

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Williams syndrome is a developmental disorder that affects many parts of the body. This condition is characterized by mild to moderate intellectual disability or learning problems, unique personality characteristics, distinctive facial features, and heart and blood vessel (cardiovascular) problems.

People with Williams syndrome typically have difficulty with visual-spatial tasks such as drawing and assembling puzzles, but they tend to do well on tasks that involve spoken language, music, and learning by repetition (rote memorization). Affected individuals have outgoing, engaging personalities and tend to take an extreme interest in other people. Attention deficit disorder (ADD), problems with anxiety, and phobias are common among people with this disorder.

Young children with Williams syndrome have distinctive facial features including a broad forehead, puffiness around the eyes, a flat bridge of the nose, full cheeks, and a small chin. Many affected people have dental problems such as teeth that are small, widely spaced, crooked, or missing. Older children and adults typically have a longer face with a wide mouth and full lips.

A form of cardiovascular disease called supravalvular aortic stenosis (SVAS) occurs frequently in people with Williams syndrome. Supravalvular aortic stenosis is a narrowing of the large blood vessel that carries blood from the heart to the rest of the body (the aorta). If this condition is not treated, the aortic narrowing can lead to shortness of breath, chest pain, and heart failure. Narrowing of other vessels, including the artery from the heart to the lungs (pulmonary stenosis) and the arteries that supply blood to the heart (coronary artery stenosis) can also occur. Other problems with the heart and blood vessels, including high blood pressure (hypertension) and stiff blood vessels, have also been reported in people with Williams syndrome. Individuals with Williams syndrome have an increased risk of complications with the use of anesthesia.

Additional signs and symptoms of Williams syndrome include abnormalities of connective tissue (tissue that supports the body's joints and organs) such as joint problems and soft, loose skin. Affected people may also have increased calcium levels in the blood (hypercalcemia) in infancy, developmental delays, problems with coordination, and short stature. Medical problems involving vision or hearing, including sensitivity to sound (hyperacusis), are frequently associated with Williams syndrome. In addition, problems with the digestive tract and the urinary system are also possible. Obesity or diabetes can develop in adulthood.

ORPHANET DEFINITION A rare genetic multisystemic neurodevelopmental disorder characterized by a distinct facial appearance, cardiac anomalies (most frequently supravalvular aortic stenosis), cognitive and developmental abnormalities, and connective tissue abnormalities (e.g., joint laxity). Facial dysmorphism is characterized by a broad forehead, bitemporal narrowing, periorbital fullness, stellate and/or lacy iris pattern, short upturned nose with bulbous tip, long philtrum, wide mouth, full lips and mild micrognathia.

Inheritance

From: MedlinePlus Genetics, National Library of Medicine

Autosomal dominant

Frequency in the source

From: MedlinePlus Genetics, National Library of Medicine

Prevalence at birth: 1-5 / 10 000; Norway; Value and class. Prevalence at birth: 1-9 / 100 000; Hong Kong; Value and class. Point prevalence: 1-5 / 10 000; Norway; Value and class. Point prevalence: 1-9 / 100 000; Hong Kong; Value and class.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Abdominal pain · Very frequent (99-80%)

An unpleasant sensation characterized by physical discomfort (such as pricking, throbbing, or aching) and perceived to originate in the abdomen.

Abnormal nervous system morphology · Very frequent (99-80%)

A structural anomaly of the nervous system.

Abnormal social behavior · Very frequent (99-80%)

An abnormality of actions or reactions of a person exhibited during social interactions with other individuals.

Abnormality of extrapyramidal motor function · Very frequent (99-80%)

A neurological condition related to lesions of the basal ganglia leading to typical abnormalities including akinesia (inability to initiate changes in activity and perform volitional movements rapidly and easily), muscular rigidity (continuous contraction of muscles with constant resistance to passive movement), chorea (widespread arrhythmic movements of a forcible, rapid, jerky, and restless nature), athetosis (inability to sustain the muscles of the fingers, toes, or other group of muscles in a fixed position), and akathisia (inability to remain motionless).

Abnormality of pelvic girdle bone morphology · Very frequent (99-80%)

An abnormality of the bony pelvic girdle, which is a ring of bones connecting the vertebral column to the femurs.

Abnormality of speech or vocalization · Very frequent (99-80%)

An abnormality in the sound (volume) or cadence (rate) of speech.

Abnormality of the cardiovascular system · Very frequent (99-80%)

Any abnormality of the cardiovascular system.

Abnormality of the neck · Very frequent (99-80%)

An abnormality of the neck.

Other findings in the same source

From: Orphanet

Additional reported features include Anxiety (Very frequent (99-80%)); Ataxia (Very frequent (99-80%)); Blepharophimosis (Very frequent (99-80%)); Broad forehead (Very frequent (99-80%)); Coarse facial features (Very frequent (99-80%)); Depression (Very frequent (99-80%)); Dysgraphia (Very frequent (99-80%)); Dysmetria (Very frequent (99-80%)); Elfin facies (Very frequent (99-80%)); Epicanthus (Very frequent (99-80%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: MedlinePlus Genetics, National Library of Medicine

Antenatal; Neonatal

Inheritance in the source

From: MedlinePlus Genetics, National Library of Medicine

Autosomal dominant

Frequency and the population described

From: MedlinePlus Genetics, National Library of Medicine

Prevalence at birth: 1-5 / 10 000; Norway; Value and class. Prevalence at birth: 1-9 / 100 000; Hong Kong; Value and class. Point prevalence: 1-5 / 10 000; Norway; Value and class. Point prevalence: 1-9 / 100 000; Hong Kong; Value and class.

Understanding the inheritance label

From: MedlinePlus Genetics

An autosomal dominant pattern means that one altered copy of a relevant gene can be sufficient for the condition. Some affected people inherit the change; others have a new change without an affected parent. The precise finding, family history and condition determine what this means for relatives.

Which doctor should you see?

The suggested department for discussing Williams syndrome is Clinical Genetics, with a clinical geneticist as the relevant type of clinician. Paediatrician (children) or physician (adults), with clinical geneticist referral.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Does the exact genetic or chromosome finding explain the observed features?
• Would a genetic counsellor help the family understand the result?
• Which organ-specific assessments are appropriate for this particular diagnosis?

Treatment discussions and follow-up

Where the source describes treatments, these are an overview of possible care, not a prescription for an individual. Ask which option applies to the confirmed diagnosis, what benefit is expected, what adverse effects to watch for and how progress will be assessed. Availability, approvals and local practice can differ from the country described in the source.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.