Williams
SyndromeWilliams syndrome occurs with a frequency of 1 in 7,500 births.
It is due to a deletion of more than 20 genes from the region q11.2 of chromosome
7. There is an "elfin"
appearance of the face with a low nasal bridge, a combination of mental
retardation with an unusual language skill; they are cheerful, but this is coupled
with outbursts of negative emotions. Supravalvular
stenosis and transient hypercalcemia (high calcium blood level) are also
often present. Signs and symptoms
The
facial appearance is characterized by a wide mouth with a large slack bottom lip;
the teeth are irregular and widely spaced. Children with Williams syndrome are
outgoing and friendly, but inappropriately easy with strangers. They have a love
of music and often have perfect pitch, but at the same time they are extremely
sensitive to loud noises (noise hypersensitivity), like guns firing, siren sounds,
fire crackers, balloons bursting etc. The aorta above the aortic valve
is widened (supravalvular stenosis) and sometimes this leads to heart problems
requiring a pediatric cardiologist. There can be the occasional kidney
defect or a lack of muscle coordination and muscle weakness. More psychological
clues are an obsession to talk to adults, but having problems forming relationships
with their peers. There is excessive talking in an inappropriate “adult” language.
Obsessional interests in certain objects like cars etc. are common as are fear
of heights. Exaggerated display of emotions (fear, anger, sadness, happiness,
excitement etc.) and uninhibited behavior create social problems. They have poor
spatial orientation, but excellent social skills. Diagnostic tests
There are specific genetic tests, namely the fluorescence in situ hybridization
(FISH) with DNA probes for the q11.2 region on chromosome 7 where this specific
deletion had occurred. Prognosis Early diagnosis
allows for earlier intervention with special educational programs. With attention
to detail and appropriate support these people can lead a relatively normal and
meaningful life. Their genetic defects are not inherited, they occurred spontaneously
and they are also not passed on to future generations.
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