Question

Why is hydrops fetalis largely restricted to Southeast Asia?

A Dietary differences between populations affect expressivity of the phenotype
B The type of malaria present in this area
C Two α-globin alleles are commonly deleted in cis in this population
D α-Thalassemia carrier status is most common in this population
E A compensating hemoglobinopathy is less common in this population

Answer 1

Hydrops fetalis is largely restricted to Southeast Asia due to the presence of α-thalassemia, a type of inherited anemia caused by abnormal hemoglobin that is a genetic adaptation to malaria. This condition increases the susceptibility to hydrops fetalis, a severe form of anemia in newborns.

Step-by-step explanation:

Hydrops fetalis is largely restricted to Southeast Asia because of the common occurrence of two α-globin alleles being deleted in cis in this population. This is known as α-thalassemia, a type of inherited anemia caused by abnormal hemoglobin that is a genetic adaptation to malaria. The presence of α-thalassemia in the Southeast Asian population leads to an increased susceptibility to hydrops fetalis, a severe form of anemia in newborns.