-A graduate student from India
March 15, 2016
The more closely related two people are, the more likely their kids will end up with some sort of genetic problem. Since the two of you are first cousins, once removed, that means your chances of having a child with a genetic problem are higher.
But as discussed here, this higher chance for cousins isn’t that bad. Yes, there is a higher chance but it is still relatively small. And for you, the chance is even a bit less since you are actually first cousins, once removed.
Different Diseases, Different Gene Combinations
So, genetic diseases often happen when someone has a version of a gene that doesn’t work. For example, people with cystic fibrosis have a CFTR gene that can’t do its job.
Remember how we have two copies of each gene?
Sometimes it takes just one nonworking gene to cause a problem. These are called dominant traits or conditions.
Autosomal Recessive Inheritance
As you may remember, recessive means both copies of a gene have to not work to have a disease. If this was the case here, then your cousin would have two nonworking copies.
But since he just contributes one of his copies, his child would also need to get a copy from the mom. If mom doesn’t have the condition, then the only way this could happen would be if she was a carrier. Carriers have one nonworking copy, but since they also have one working copy, they don’t have the disease.