Williams syndrome

Williams syndrome (WS) is a genetic disorder that affects many parts of the body. Facial features frequently include a broad forehead, short nose and full cheeks, an appearance that has been described as 'elfin'. Mild to moderate intellectual disability with particular problems with visual spatial tasks such as drawing and fewer problems with language are typical. Those affected often have an outgoing personality and interact readily with strangers. Problems with teeth, heart problems, especially supravalvular aortic stenosis, and periods of high blood calcium are common. Williams syndrome (WS) is a genetic disorder that affects many parts of the body. Facial features frequently include a broad forehead, short nose and full cheeks, an appearance that has been described as 'elfin'. Mild to moderate intellectual disability with particular problems with visual spatial tasks such as drawing and fewer problems with language are typical. Those affected often have an outgoing personality and interact readily with strangers. Problems with teeth, heart problems, especially supravalvular aortic stenosis, and periods of high blood calcium are common. Williams syndrome is caused by a genetic abnormality, specifically a deletion of about 27 genes from the long arm of one of the two chromosome 7s. Typically this occurs as a random event during the formation of the egg or sperm from which a person develops. In a small number of cases, it is inherited from an affected parent in an autosomal dominant manner. The different characteristic features have been linked to the loss of specific genes. The diagnosis is typically suspected based on symptoms and confirmed by genetic testing. Treatment includes special education programs and various types of therapy. Surgery may be done to correct heart problems. Dietary changes or medications may be required for high blood calcium. The syndrome was first described in 1961 by New Zealander John C. P. Williams. Williams syndrome affects between 1 in 7,500 to 1 in 20,000 people at birth. Life expectancy is less than that of the general population, mostly due to the increased rates of heart disease. The most common symptoms of Williams syndrome are heart defects and unusual facial features. Other symptoms include failure to gain weight appropriately in infancy (failure to thrive) and low muscle tone. Individuals with Williams syndrome tend to have widely spaced teeth, a long philtrum, and a flattened nasal bridge. Most individuals with Williams syndrome are highly verbal relative to their IQ, and are overly sociable, having what has been described as a 'cocktail party' type personality. Individuals with Williams syndrome hyperfocus on the eyes of others in social engagements. Individuals with Williams syndrome experience many cardiac problems, commonly heart murmurs and the narrowing of major blood vessels as well as supravalvular aortic stenosis. Other symptoms may include gastrointestinal problems, such as severe or prolonged colic, abdominal pain and diverticulitis, nocturnal enuresis (bed wetting) and urinary difficulties, dental irregularities and defective tooth enamel, as well as hormone problems, the most common being high blood calcium. Hypothyroidism has been reported to occur in children, although there is no proof of it occurring in adults; adults with WS have a higher risk of developing type 2 diabetes, with some cases apparent as young as 21 years old. Individuals with Williams syndrome often have hyperacusia and phonophobia which resembles noise-induced hearing loss, but this may be due to a malfunctioning auditory nerve. However, individuals with WS can also tend to demonstrate a love of music, and they appear significantly more likely to possess absolute pitch. There also appears to be a higher prevalence of left-handedness and left-eye dominance. Ophthalmologic issues are common in Williams syndrome. Up to 75% of subjects in some studies have strabismus (ocular misalignment), particularly esotropia, due to inherent subnormal binocular visual functionand cognitive deficits in visuospatial construction. Individuals with Williams syndrome have problems with visual processing, but this is related to difficulty in dealing with complex spatial relationships rather than depth perception per se. Because of the multiple genes that are missing in people with Williams syndrome, there are many effects on the brain, including abnormalities in the cerebellum, right parietal lobe, and left frontal cortical regions. This pattern is consistent with the visual-spatial disabilities and problems with behavioral timing often seen in Williams syndrome.