What chromosome is connected with Williams syndrome?

We know that most individuals with Williams syndrome are missing genetic material on chromosome #7 including the gene that makes the protein elastin (a protein which provides strength and elasticity to vessel walls.) It is likely that the elastin gene deletion accounts for many of the physical features of Williams syndrome. Some medical and developmental problems are probably caused by deletions of additional genetic material near the elastin gene on chromosome #7. The extent of these deletions may vary among individuals. If a patient has 2 copies of the elastin gene (one on each of their chromosomes #7), they probably do not have WS. If the individual only has one copy, the diagnosis of WS will be confirmed. Virtually all (98-99%) persons with typical features of WS will have a deletion of the elastin gene. In more technical terms: Williams syndrome is the result of a deletion of the 7q11.23 region of chromosome #7 containing the elastin gene and is believed to be a contiguous gene syndrome. Diagnosis of Williams syndrome is confirmed by dual colour FISH using a specific probe and a control probe.

Find more information at http://www.williams-syndrome.org/