The adverse effects with combined 3-drugs therapy and monotherapy with AZT were respectively: neutropenia 55% and 39%; anemia 50% and 39%; low platelet count 0 and 3%; elevation in AST 3% and 3%; elevation in ALT 0 and 1%; hyperbilirubinemia 19% and 42%. The gene discussed is GPT; the disease is neutropenia.