91–96% demonstrate inattention, 75% impulsivity, 59–71% hyperactivity 46–74% tantrums, 32–60% disobedience, and 25–37% fighting and aggressive behavior.In one experiment, a group of children with Williams syndrome showed no signs of racial bias, unlike children without the syndrome. They did show gender bias, however, to a similar degree to children without the syndrome, suggesting separate mechanisms for these biases. Cause
Williams syndrome is a microdeletion syndrome caused by the spontaneous deletion of genetic material from the chromosomal region 7q11.23. This is a hemizygous deletion, which results in haploinsufficient expression of the 25–27 genes in this region. CLIP2, ELN, GTF2I, GTF2IRD1, and LIMK1 are among the genes typically deleted. Hemizygosity for the ELN gene, which codes for the extracellular matrix protein elastin, is associated with connective-tissue abnormalities and cardiovascular disease (specifically supravalvular aortic stenosis and supravalvular pulmonary stenosis). Elastin insufficiency may also contribute to distinct faces, harsh or hoarse voice, hernias, and bladder diverticula often found in those with Williams syndrome. Hemizygosity in LIMK1, GTF2I, GTF2IRD1, and perhaps other genes may help explain the characteristic difficulties with visual–spatial tasks. Additionally, some evidence shows that the hemizygosity in several of these genes, including CLIP2, may contribute to the unique behavioral characteristics, learning disabilities, and other cognitive difficulties seen in WS. Diagnosis
According to the Williams Syndrome Association, its diagnosis begins with the recognition of physical symptoms and markers, which is followed by a confirmatory genetic test.
In particular, people with Williams syndrome experience challenges in visual-motor skills and visuospatial construction. Most affected people are unable to spatially orient themselves and many experience difficulty when given a task that requires even the most basic visual problem-solving. Many adults with Williams syndrome cannot complete a simple six-piece puzzle designed for young children, for example. These visuospatial deficits may be related to damage to the dorsal cortical pathway for visual processing.Despite their physical and cognitive deficits, people with Williams syndrome exhibit impressive social and verbal abilities. Williams patients can be highly verbal relative to their IQ. When children with Williams syndrome are asked to name an array of animals, they may well list a wild assortment of creatures such as a koala, saber-toothed cat, vulture, unicorn, sea lion, yak, ibex and Brontosaurus, a far greater verbal array than would be expected of children with IQs in the 60s. Some other strengths that have been associated with Williams syndrome are auditory short-term memory and facial recognition skills. The language used by people with Williams syndrome differs notably from unaffected populations, including people matched for IQ. People with Williams syndrome tend to use speech that is rich in emotional descriptors, high in prosody (exaggerated rhythm and emotional intensity), and features unusual terms and strange idioms.Among the hallmark traits of people with Williams syndrome is an apparent lack of social inhibition.