Williams syndrome Sequencing

A genetic disorder characterized by mental retardation which can range from mild to severe. Personality features such as overfriendliness, general anxiety, and attention deficit disorder. Facial features include narrow forehead, fullness about the eyes, short nose, flat midface, full lips, wide mouth, small jaw, and prominent earlobes. Narrowing of the aorta, just above the valve, is the most common and important cardiovascular abnormality. Hypercalcemia and hypercalciuria are also seen in patients with this syndrome.

Williams syndrome is inherited in an autosomal dominant manner and is due to a small chromosome deletion. Most cases are new occurrences but parent-to-child transmission is known. The region deleted is from chromosome 7 (band 7q11) and includes the ELN gene. The syndrome is due not only to the loss of ELN but to a loss of a series of adjacent genes.

Sequencing is the first tier test for this disorder. If no mutation is found we recommend FISH as the second tier test.

Methodology: Sequencing of entire coding region

Purpose: Confirmation of Clinical Diagnosis

ICD-9 Code 758.89

Test Requisition: Sequencing Requisition

CPT Codes: 81479 Cost: $1193.00

Turn-around-time: 5-6 weeks