Williams syndrome is a genetic disorder that affects many parts of the body. The condition can cause facial features like a broad forehead, small chin, wide mouth, full cheeks, and a short, upturned nose, which have sometimes been described as “elfin” (elf-like). It usually causes a mild to moderate intellectual disability, which affects how people think and learn, and may especially affect visual spatial tasks like drawing. People with Williams syndrome usually have good verbal skills (speech) but often take longer than other children to learn how to speak. Many people with the condition have an outgoing and happy personality, enjoy socializing, and have a lot of empathy. Medical issues such as heart problems, teeth problems, and high blood calcium are common.
Williams syndrome is caused when one of about 27 genes is deleted from the long arm of one of the two copies of chromosome 7. This is usually a random event that happens when the sperm or egg that a person develops from is being formed. The different traits of Williams syndrome have been linked to the loss of specific genes. The diagnosis is usually suspected based on symptoms and proven by genetic testing.
The syndrome was first described in 1961 by New Zealander John C. P. Williams. It is a rare condition; around one in 7,500 to 20,000 people are born with it. Those with Williams syndrome have a lower life expectancy (number of years they are expected to live) than the general population, mostly because they are more likely to have heart disease.
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