Hereditary orotic aciduria Type-I is due to deficiency of ?

Ans. is `d' i.e., All of the above Orotic aciduria is a hereditary disorder which can result from a defective enzyme in pyrimidine synthesis. There is a defect in the multifunctional enzyme UMP synthase which has two activities :?Orotate phosphoribosyl transferaseOrotic acid decarboxylase (orotidylate decarboxylase)UMP synthase conves orotic acid to UMP. Thus, in defect of UMP synthase orotic acid can not be conveed to UMP and is excreted in urine - orotic aciduria.There are two types of orotic aciduria.Type 1 :- There is deficiency of both the components of UMP synthase, i.e. orotate phosphoribosyl transferase and oritidylate decarboxylase.Type II :- There is deficiency of only orotidylate decarboxylase.