Question

Α-thalassemia due to a three gene deletion presents with HbH disease and severe anemia. How many total genes are there?

1) 2
2) 3
3) 4
4) 5

Answer 1

The total number of genes involved in α-thalassemia due to a three gene deletion is 4. When there is a deletion of three genes, it leads to the formation of abnormal hemoglobin called HbH, which is associated with severe anemia.

Step-by-step explanation:

The total number of genes involved in α-thalassemia due to a three gene deletion is 4.

In alpha-thalassemia, there are four genes that play a role in the synthesis of the α-chain of globin. These genes are usually present in pairs, and when there is a deletion of three genes, it leads to the formation of abnormal hemoglobin called HbH.

HbH disease is characterized by severe anemia and a decrease in the levels of hemoglobin. The lack of α-chain results in the formation of different combinations of β and γ chains, leading to impaired transport of oxygen by Hb.