Mr. Wayne is a 38-year-old man with a significant family history of elevated cholesterol levels. His father died at age 42 from
a massive heart attack secondary to elevated cholesterol and triglycerides, and two of his older siblings are currently taking medications to lower their cholesterol levels. Mr. Wayne makes an appointment to discuss his risk for hypercholesterolemia. The nurse recognizes that Mr. Wayne is at risk for familial hypercholesterolemia because this is an autosomal dominant inherited condition. Mr. Wayne asks what chance his children have of developing familial hypercholesterolemia. How should the nurse respond? Explain the phenomenon of penetrance observed in autosomal dominant inheritance.
The nurse should tell him that there are minimum 50% chances of his children develop this condition.
Explanation:
Mr. Wayne carries autosomal dominant disorders can be heterozygous or homozygous if it's heterozygous, a mutant and a normal allele present in this condition there is a 50% chances offspring will carry the normal allele and a 50% chances offspring will carry the mutant allele if Mrs. Wayne carries normal alleles.
If Mr. Wayne having homozygous conditions then all offspring will carry a mutant allele even if Mrs. Wayne carries normal alleles.
(heterozygous condition)
Xx cross xx (x = recessive allele) (X = dominant allele)
↓
Xx, Xx, xx, xx
(Homozygous condition)
XX cross xx
↓
Xx, Xx, Xx, Xx
Thus, the nurse should tell him that there are minimum 50% chances of his children develop this condition.
