“Great, so this looks like an accurate representation of your family, right?” Dr. Ciletti asked.
“Looks good to me,” replied Greg.
“My family is so small, there’s not much to miss until you get to my grandparents,” said Olga.
“Well, factor VIII deficiency and myotonic dystrophy are inherited in completely different ways. Come to think of it, you asked about CF as well and …”
“CF?” asked Greg.
“Cystic fibrosis,” Dr. Ciletti continued. “I was about to say that cystic fibrosis is inherited in a manner different than both of the other diseases you are concerned about, but let’s tackle them one at a time.”
“Myotonic dystrophy is an autosomal dominant disease and it is the easiest to pick out of a pedigree. Now Greg, even though you have an uncle and aunt as well as a grandmother who all have the disease, you don’t and there is no way that you will pass this disease on to your children. So that is the first piece of good news.”
“But don’t a lot of genetic diseases skip a generation?” Greg asked. “And even if doesn’t, my mom has two siblings with the disease. Could she be a carrier and just pass the disease on to me? For that matter, could I be a carrier?”
“Yes, could he be a carrier?” Olga added.
“Absolutely not,” Dr. Ciletti said. “Let me show you why.”
Originally published at http://www.sciencecases.org/sickness_and_health/sickness_and_health2.asp
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