Tuesday, February 18, 2014

Genetic Testing- No Small Thing

We got the results back from the genetic testing done a month ago: everything is negative! She had blood drawn and sent to the U of MN Cytogenetics Laboratory for a CGH analysis (comparative genomic hybridization) in January. The results took so long to come back because they had to analyze her DNA for any added or missing chromosomes associated with  known genetic disorders. Thankfully, there were no abnormalities detected, although this analysis only checks for certain common genetic disorders.

The results we got last week from the Cystic Fibrosis test were not quite so positive. She was found not to have CF but she does carry a mild form of CF in her genes. The mutation is called (TG)11-5T variant. This test was a blood draw taken on the same date but was run separately from the above sample. The testing was similar though; Ambry Genetics Laboratory ran sequencing and deletion/duplication studies of the CFTR gene.

So while we're thrilled that she doesn't have the CF disorder, it was hard for me to learn that she is a carrier of CF. This also means that either I, the sperm donor, or both of us are carriers of the mutation as well. The cryobank tests for several genetic disorders, including CF, but they don't test for the variant Audrey has. Our genetic counselor is getting more information about when and how the testing for CF is done there so she can clarify the possibility of the donor being a carrier. Understandably, the parents of Audrey's half-siblings are worried about this as well.

It's possible for me to have genetic testing done on myself to see my carrier status, but it's extremely expensive and we are already struggling financially. I'm more concerned about this than Ryan is regarding our future children as it's possible for them to either get CF or become a carrier.

If only one parent is a carrier then the baby has a 50% chance of being a carrier. If both parents are carriers than the baby has a 25% chance of having CF or related symptoms. Apparently 10% of the population is a carrier of CF so it's not all that uncommon, and even if a person has CF that doesn't mean they have the classic form that is commonly thought of. Someone could have CF and not even know it if the symptoms are mild enough or non-existent.

So although we're glad to know that the cause of her FTT probably isn't a genetic disorder, this experience was a bit like opening a can of worms. Now we know about the CF carrier status, while we probably would have remained blissfully unaware of that otherwise. But at least Audrey will have that information when she wants to decide about having children, whereas Ryan and I were completely blindsided by his infertility diagnosis, also a genetic condition.

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