Question

Chronic non-spherocytic hemolytic anemia is seen in which WHO class of G6PD deficiency?

• A. Class I
• B. Class II
• C. Class III
• D. Class IV

Hint:

The most severe variant with under 10 percent activity haemolyses for life.

Answer 1

The Correct Option is A

Step 1: The WHO classifies G6PD variants by the degree of enzyme deficiency and the severity of haemolysis. Chronic (congenital) non-spherocytic haemolytic anaemia is the feature of Class I variants, so the answer is option a.

Step 2: Class I variants have such severe G6PD deficiency (less than 10 percent of normal activity) that lifelong haemolysis occurs even without infection or drug exposure. Mutations often lie at the glucose-6-phosphate or NADP binding sites, crippling enzyme function.

Step 3: Class II variants (for example G6PD Mediterranean) also have severe deficiency but cause only intermittent acute haemolysis triggered by infection, drugs or fava beans. Class III variants (for example G6PD A-) have moderate deficiency with episodic haemolysis.

Step 4: Class IV variants have normal activity with no haemolysis and Class V have increased activity, so neither produces chronic haemolytic anaemia. This confirms Class I as the correct answer.