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A female asked:

My fianc has a sister with preder willi's syndrome... what kind of risk does our future child have...is it genetic ?

1 doctor answer5 doctors weighed in
Dr. Lois A Freisleben-Cook
Pediatrics 36 years experience
It's complex: Prader Willi Syndrome is caused by the absence of a small part of chromosome 15 either through a microdeletion or through a phenomenon called uniparental disomy whereby both copies of chromosome 15 come from the mother resulting in the paternally imprinted segment being absent. A more rare situation is one in which the process of imprinting is abnormal in the father. This is because the imprinting gene is defective. The greatest recurrence risk is in this latter situation. Although the imprinting defect can be a spontaneous occurrence there can be up to a 50 percent risk that a normal male sibling will carry it and father a child with PWS. Learning the details of his sister’s chromosome studies and consultation with a genetic counselor can guide recommendations for testing your fiancee and determination of risk for your children.
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Dr. Al Hegab
Dr. Al Hegab commented
Allergy and Immunology 41 years experience
Great job Dr Cook
Apr 12, 2015
Dr. Richard Roberts
Pediatrics 47 years experience
I agree, and would also mention that prenatal diagnosis is possible.
Jun 28, 2015

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Last updated Jun 28, 2015
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