Williams syndrome

Williams syndrome is a rare genetic disorder. Williams syndrome is characterised by distinctive physical features and behaviours including a distinctive facial appearance, mild intellectual disability and an overly sociable personality.

A missing segment (a ‘deletion’) of genetic material on chromosome 7 is the cause. These deletions occur randomly. About one in every 20,000 babies is born with Williams syndrome. Boys and girls are equally affected, and the disorder is found across all races and countries. There is no cure.

Treatment aims to support the individual and manage associated symptoms. The outlook depends on the degree of severity. In some cases a person with Williams syndrome can complete school, work and look after themselves. However other individuals may need lifelong care.

Typical features
Most people with Williams syndrome share a wide range of physical, social and cognitive (thinking and acquiring knowledge). These characteristic features may occur to a greater or lesser degree.

Some common physical traits include:

• Distinctive facial features – including long upper lip, small chin, generous lips, chubby face, upturned nose and flattened nose bridge. The overall picture is usually quite recognisable to the experienced eye. Some may have a squint.
• Weight and growth problems – the newborn may have a low birth weight and gain weight slowly. Adults are usually shorter than average.
• Feeding difficulties – the baby may have problems with feeding, including swallowing difficulties and excessively slow eating.
• Hyperacusis – extreme sensitivity to sound, which may include being startled by ordinary noise levels.
• Dental problems – including smaller than normal teeth, oddly shaped teeth, widely spaced teeth and a misaligned bite.
• Cardiovascular defects – common heart problems include narrowed aorta (aortic stenosis) and narrowed pulmonary artery (pulmonary stenosis).
• Hypercalcaemia – higher than normal levels of calcium circulating in the blood.
• Colic – it is thought that the colic or irritability frequently experienced by babies with Williams syndrome may be caused by hypercalcaemia.
• Hernias – including groin and umbilical (belly button) hernias.
• Kidney problems – including variations in shape and function.
• Muscle and joint problems – including poor muscle tone, weak muscles, overly loose joints, muscle contractures and poor physical coordination.

• Intellectual disabilities – such as developmental delays, below average IQ, learning difficulties, poor spatial skills and attention deficit hyperactivity disorder (ADHD).
• Overly sociable personality – typically the person with Williams syndrome is inappropriately outgoing, with no fear of strangers or social interaction.

• Medical history
• Physical examination to check for typical features
• Blood test to check for elevated calcium levels (although high calcium levels are not always involved)
• Fluorescent in situ hybridisation (FISH) chromosome test to check for the deletion of the elastin gene on chromosome 7 – this specific test requires a blood sample.

• Speech therapy.
• Social ‘training’ – for example, how to greet people appropriately instead of automatically kissing and hugging.
• Regular medical monitoring of heart and blood vessel defects and any other physical problems that could present complications.
• Surgery to correct heart and blood vessel defects, if necessary.
• Dental and orthodontic treatment.
• Physical therapy from a physiotherapist
• Occupational therapy.

• Your doctor
• Williams Syndrome Association of SA Inc Tel. (08) 8258 3867 or (08) 8285 3776
• Genetic Health Services Victoria, Royal Children’s Hospital Tel. (03) 8341 6200.

• Williams syndrome is a rare genetic disorder that is caused by the deletion of genetic material on chromosome 7.
• Typical characteristics include distinctive facial features, mild intellectual disability and an overly sociable personality.
• Williams syndrome may be undiagnosed, which means that many people with the disorder fail to get the support and treatment they need until later in life.

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