Question

31. Below are concordance rates for five different human disorders studied in monozygotic (MZ) and dizygotic (DZ) twins.

Concordance
Disorder MZ DZ
A 100% 50%
B 17% 16%
C 56% 11%
D 100% 25%
E 50% 100%
One of the above disorders is in part caused by significant genetic effects. In addition to a significant genetic contribution toward the disorder, there are also significant environmental effects that contribute toward the disorder phenotype. Which of the above disorders would this description most likely apply to?
a. A
b. B
c. C
d. D
e. E

Answer 1

Disorder A, with a 100% concordance rate in MZ twins and 50% in DZ twins, most likely includes both significant genetic effects and environmental contributions.

Step-by-step explanation:

The disorder that most likely applies to the description of having both significant genetic effects and environmental contributions is Disorder A. This disorder shows a concordance rate of 100% in monozygotic (MZ) twins and 50% in dizygotic (DZ) twins.

The high concordance rate in MZ twins, who share 100% of their genes, suggests a strong genetic component. However, the substantial drop in concordance for DZ twins, who share only about 50% of their genes, indicates that environmental factors also have a significant role in the expression of this disorder.