Williams Syndrome, Microdeletion 7q11.23

Elastin-Wiliams-syndrome

Klinische Symptomatik

The Williams-Beuren syndrome is characterized by supravalvular aortic stenosis, facial dysmorphias and infantile hypercalcemia. The facial dysmorphic features include prominent forehead with periorbital wellings, middle face hypoplasia, epicanthus, short palpebral fissures, everted nasal base, full cheeks and broad everted lower lip. The voice is often coarse, the teeth hypoplastic. Many affected patients are mentally retarded with a friendly and social nature.

Genetik

The Williams-Beuren syndrome is cause by a microdeletion in the ELN (elastin) gene in the long arm of chromosome 7 (7q11.23), leading to partial monosomy for 7q11.23 which is detectable in 96% of the patients. As in other microdeletion syndromes, most cases are sporadic. However, there are families with more affected patients suggesting an autosomal dominant inheritance pattern with variable expression. Apart from the deletion in the elastin gene additional genes located in the neighborhood of the elastin gene can be involved ("contiguous gene" syndrome) and contribute to the variation of the clinical phenotype.

Häufigkeit

1 : 10 000 to 1 : 20 000

 

Diagnostik