Hereditary orotic aciduria Type-I is due to deficiency of: (A) Orotate phosphoribosyl transferase, (B) Ribonucleotide reductase, (C) Dihydroorotase, (D) Dihydroorotate dehydrogenase
Answer is A. The orotic aciduria is a consequence of the inability of severely damaged mitochondria to utilize carbamoyl phosphate, which then becomes available for cytosolic overproduction of orotic acid.Type-I orotic aciduria reflects a deficiency of both orotate phosphoribosyltransferase and orotidylate decarboxylaseThe rarer Type-II orotic aciduria is due to a deficiency only of orotidylate decarboxylaseRef: Harper 27e, page no:354