Question

Which one of the following would be expected to increase recurrence risk the most for a multifactorial disorder?

(A) The disorder occurs in a third-degree relative.
(B) There is one affected second cousin.
(C) There is a first cousin with mild disease.
(D) The parents are first cousins.

Answer 1

First cousins as parents would significantly increase the recurrence risk for a multifactorial disorder because they share more genetic material, raising the likelihood of both carrying the same detrimental variants.

Step-by-step explanation:

The student asked which scenario would increase the recurrence risk the most for a multifactorial disorder. Among the options given, the scenario where the parents are first cousins (D) would be expected to increase the recurrence risk the most for a multifactorial disorder. This is due to the fact that first cousins share a higher amount of genetic material compared to more distant relatives, which increases the probability of both parents carrying the same gene variants that might contribute to the development of a multifactorial disorder. This is particularly relevant in the context where associated genetic components follow an autosomal recessive pattern, as two carriers have a higher chance of having an affected offspring.