If only maternal alleles are present, PWS is confirmed. If the PWS is due to a deletion, the patient's father is studied via FISH to rule out a balanced insertion or an inherited deletion not expressed in the father. If only paternal alleles are present, AS is confirmed. If the AS is due to a deletion, the patient's mother is studied via FISH to rule out a balanced insertion or an inherited deletion not expressed in the mother. If all of the above studies are normal, but the diagnosis of PWS or AS is still strongly suspected, cases should be referred to one of several research laboratories.
Prenatal diagnosis is complicated but can be accomplished.
Genetic counseling and testing is recommended for individuals with symptoms of PWS or AS, or at-risk asymptomatic individuals who are at least 18 years of age. Ship sample at room temperature within 24 hours. If you cannot send the specimen the same day as it was collected, hold at room temperature and send within 48 hours. Prenatal Call first.