In Sickness and in Health by Barry Chess

Part III—Autosomal Recessive Traits

“Well, I certainly feel better about that,” said Greg. “I guess there is no reason to worry about passing on MD to our children. They’ll just have to worry about inheriting their father’s incredible good looks, fabulous sense of humor, creativity …”

“And modesty … Hold on a second, God’s gift to the world,” Olga chimed in. “We still haven’t talked about factor VIII deficiency, which is why we came here in the first place.”

“Well,” Dr. Ciletti began, “factor VIII deficiency is what’s known as a sex-linked disease. Before we get to that, let’s take a look at a disease with a slightly simpler mode of inheritance. Many traits, whether or not they are considered to be diseases, are described as autosomal recessive traits. These are the ones you alluded to earlier when you talked about diseases that skip generations and about people being carriers. Some common recessive traits include albinism, sickle cell disease, and cystic fibrosis, which I promise we will get to, Olga. Now, let’s look at some of the rules governing these types of traits.”

Questions

1. What are the hallmarks of an autosomal recessive trait?
2. What does consanguineous mean? Why is this concept especially important when discussing recessive genetic disorders?
3. What is it about the inheritance pattern of factor VIII deficiency seen in Greg and Olga’s pedigree that point toward it not being an autosomal recessive trait?

References

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