Williams 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.
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.
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.