<prompt> Most common enzyme deficiency causing hemolytic anemia?Pyruvate kinaseHexokinaseGlucose-6-phosphate dehydrogenaseGucosephosphate isomerase  <response>: Ans. c Glucose-6-phosphate dehydrogenase Ref. H - 18thch. 106; Harper 27thpg. 127Genetic deficiency of glucose 6-phosphate dehydrogenase, the first enzyme of the pentose phosphate pathway, is a major cause of hemolysis of red blood cells, resulting in hemolytic anemia and affecting approx 100 million people worldwide.GLUCOSE-6-PHOSPHATE DEHYDROGENASE G6PD DEFICIENCY It is the most common human enzyme deficiency.0 It is the most common enzyme deficiency causing hemolytic anemia.0 Glucose-6-phosphate dehydrogenase G6PD deficiency is an X-linked recessive disease featuring nonimmune hemolytic anemia in response to a number of causes.0 The classic reaction to consumption of broad beans has led to the commonly used term favism. It confers protection against malaria, in particular the form of malaria caused by Plasmodium falciparum.Q Drugs that can cause hemolysis in G6PD deficiency:- Primaquine an antimalarial- Sulphonamide antibiotics- Sulphones e.g., dapsone, used against leprosy- Other sulphur-containing drugs: glibenclamide an antidiabetic drug- Nitrofurantoin an antibiotic often used for urinary tract infections- Vitamin K analogues Lab features of GPD deficiency:- In active G6PD, Heinz bodies aggregates of protein can be seen in RBCs on a blood film;0- Haptoglobin is decreased in hemolysis;- A direct antiglobulinCoombs test-negative, as hemolysis in G6PD not immune-mediated;- When there are sufficient grounds to suspect G6PD, a direct test for G6PD is the Beutler fluorescent spot test, which has largely replaced an older test the Motulsky dye-decolouration test.- The Beutler fluorescent spot test is a rapid and inexpensive test that visually identifies NADPH produced by G6PD under ultraviolet light. 