The American College of Medical Genetics has described two approaches to laboratory diagnosis. The first approach, to be used in cases with a high degree of suspicion of AS or PWS, is DNA methylation analysis which will detect cases caused by deletion, uniparental disomy (UPD) or imprint defects. If the results are positive, a test for uniparental disomy may be recommended to determine the specific cause and the recurrence risk. UPD is the cause of approximately 26% of the cases of Prader-Willi syndrome and about 3% to 5% of the cases of Angelman syndrome.

TESTING METHODOLOGY:

• PCR amplification of several polymorphic short tandem repeat (STR) markers located in chromosome 15q11.2-q13.

• Blood EDTA (purple top) tubes:  

            Newborn: minimum 1-2 mL          

            Child/Adult: prefer 2 tubes of 3-5 mL

• Prenatal testing: Please contact the laboratory for instructions.

TURNAROUND TIME: 3 weeks

CPT CODES: 83890x3, 83894x3, 83901x6, 83912