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
aortic 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 obsessive compulsive disorder in children to talk to adults, but
having behavioral problems such as 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 such as the one for "special needs students". 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. |
