Ask Nurse Lynn: Procreation and Genetics in PWS


Female, 34, Deletion

My daughter continues to wonder how/why some ladies with PWS have been able to conceive, give birth. As a teenager, an ultrasound determined that she had “follicles”, but she’s not ever menstruated. She continues to want to investigate the possibility of becoming pregnant. We’ve explained that this is highly unlikely, but she’s learned of a handful of women with PWS who have … Your thoughts, please.

Nurse Lynn’s Response:

I have consulted with one of our experts to help in answering your question. The presence of ovarian follicles does not equate with the ability to ovulate, or the ability to carry a pregnancy to term. Depending on the exact molecular/genetic cause of PWS, a viable fetus may not be possible. Articles and narratives of the four known pregnancies in women with PWS suggest that the gestations and deliveries were uncomplicated. Three babies were delivered by planned caesarean sections. None of the mother’s breast fed nor were they able to bond with the children. The infants were cared for by others, most often relatives. Common for all was an incapacity to put the needs of the child ahead of their personal needs and desires, especially about food.

The genetics of the children born to mothers with PWS has varied. Theoretically, the chance of a fertile woman with PWS having a non-PWS baby depends on what genetic type of PWS the mother has. A woman with PWS due to uniparental disomy (UPD) is not at risk of passing on a genetically altered chromosome 15 for PWS. A woman with PWS due to a deletion has a 50% chance with each pregnancy of passing on the chromosome with the deletion and having a baby with Angelman syndrome (AS). AS results from deletion or mutation of the maternal chromosome 15 (q11-q13 region), so if the mother passes along her own maternally derived chromosome 15, the baby will be unaffected; but if she passes on her paternally derived chromosome 15 with the deletion instead, then the baby will have AS. Characteristic symptoms of AS are severe developmental delay and/or intellectual disability, little or no speech, movement and balance disorders, and a unique behavior with an inappropriate happy demeanor that includes frequent laughing, smiling, and excitability. Many have profound sleeping problems and epilepsy. In the four documented cases of pregnancies in women with PWS, two of the children had normal chromosome 15 (mothers had deletion and UPD, respectively), the other two had AS (mothers had both deletion).

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