Question

Genetic disease blue sclera is determined by an autosomal dominant allele. The eyes of individuals with this allele have bluish sclera. These same individuals may also suffer from fragile bones and deafness. This is an example of
a. incomplete dominance.
b. pleiotropy.
c. epistasis.
d. codominance.
e. linkage.

Answer 1

Answer:

b. Pleiotropy

Explanation:

The term “pleiotropy“ refers to a situation in which variants in a single given gene have a number of different, seemingly unrelated effects in the resulting phenotype.

For instance: patients with mutations in the COL1A1 gene (codifying for collagen alpha-1 chain) may present with a genetic disease called “osteogenesis imperfecta”, characterized by (among other findings) bluish sclera, brittle bones, and deafness. All those disparate clinical manifestations may be traced back to the inability of the body to produce normal type 1 collagen.