A 4 year old girl presented to hospital with failure to thrive. Her peripheral blood smear showed megaloblastic anemia. Vitamin B12 & folate were given but anemia did not improve. Enzyme assay from the cultured PBMC showed deficiency of OP (Orotate Phospho Ribosyl Transferase). What could be the probable diagnosis ?: (A) Orotate deficiency, (B) Gout, (C) Orotic aciduria, (D) SCID
Answer is C. Orotic aciduria Due to deficiency of orotate phosphoribosyl transferase and OMP decarboxylase Leads to defect in DNA Synthesis Characterizedby : Excretion of orotic acid in urine, Severe anemia Megaloblastic Not improved with folate /vitamin B12/vitamin C Retarded growth Rx- Feeding diet rich in uridine / cytidine