Williams syndrome (WS), also called Williams-Beuren syndrome (WBS), is a genetic, neurodevelopental disorder in which chromosome seven is missing about 26 genes. The disorder is named after Dr. J. C. P. Williams of New Zealand, who first identified it in 1961. The disorder is rare, affecting only one person in 7,500 to 20,000.
Williams syndrome sufferers are characterized by "elfin" facial features, and a low nasal bridge, a very sociable and cheerful demeanor, and mental retardation coupled with musical and verbal skills. They are also prone to cardiovascular problems, including aortic or pulmonary valve stenosis, a heart malformation impeding bloodflow, and hypercalcaemia, or elevated calcium levels in the blood. Those with WS also tend to be left-handed and left-eye dominant. There is currently no cure for WS, though the symptoms, such as cardiovascular problems, can sometimes be treated or alleviated.
Children born with Williams syndrome often have a low birth weight and are slow to gain weight. As adults, they are typically smaller than average. Low muscle tone, lax joints, and joint stiffness are also common, though physical therapy can help alleviate such problems. Because of low muscle tone, people with WS are also prone to inguinal hernias. Kidney and dental malformations are also common in those with Williams syndrome, and child sufferers often exhibit difficulty feeding as a result of dental abnormalities and low muscular tone.
People with Williams syndrome have difficulty with spatial relations and visual processing. They also tend to lack common sense, and are very comfortable with strangers. Those with WS are known to be unusually friendly, polite, and cheerful, and they enjoy talking with others. However, they also often have higher levels of anxiety than others, and are more prone to phobias. Attention deficit disorder is another common issue.
One of the most striking characteristics of those with Williams syndrome is their love of music. People with WS are more likely than others to have perfect pitch, and many are very musically talented. However, they are also prone to hyperacusis, or heightened sensitivity to certain sounds, such as high-pitched sounds. Phonophobia, the fear of loud sounds, is also common in those with Williams syndrome. These auditory disorders are similar to those affecting people with noise-induced hearing loss, and may be due to auditory nerve malfunction. Hyperacusis may also be a cause of the high anxiety levels common to those with Williams syndrome.