WILLIAMS SYNDROME
A fluorescent in situ hybridization (FISH) test is offered to identify the microdeletion on chromosome 7 (q11.23) associated with Williams syndrome.
REASONS FOR REFERRAL:
Individuals with distinct "elfin" facial features, growth retardation, intermittent infantile hypercalcemia, supravalvular aortic stenosis and peripheral pulmonic stenosis, mild to moderate mental retardation and unique personality (Williams syndrome).
TESTING METHODOLOGY:
Fluorescence in situ hybridization (FISH) is the application of fluorescently-labeled DNA probes to metaphase chromosomes or interphase nuclei for the detection of chromosome abnormalities such as aneuploidy, structural rearrangements and microdeletions. Approximately 97% of patients with Williams syndrome have deletions detected by FISH. The assay uses the elastin gene (ELN) probe located at 7q11.23 and a chromosome 7 control probe. Analysis is based on fluorescent signals present in 10 to 20 labeled metaphases.
SPECIMEN REQUIREMENTS:
Newborn: minimum 1-2 mL
Child/Adult: minimum 3-5 mL
If prenatal testing is required, contact the laboratory regarding specimen requirements.
Transport at ambient temperature. Specimen cannot be frozen.
A Cytogenetic Laboratory Test Requisition must accompany the specimen. For shipping and handling information, refer to Cytogenetic Specimen Instructions.
Contact the Cytogenetic Laboratory at 918-502-1721 for further information.
TURNAROUND TIME: 10 days
CPT CODES: