To the Editor.
—I read with great interest the article in the March 1991 issue of the Archives by Sakamoto et al.1 However, the enzyme deficiency quoted by Sakamoto et al for type 1 primary hyperoxaluria was incorrect. Danpure et al,2 in 1986, established that the primary enzymatic deficiency is hepatic peroxisomal alanine:glyoxylate aminotransferase (AGT; EC 126.96.36.199). The decreased α-ketoglutarate glyoxylate carboligase quoted by Sakamoto et al is caused by secondary mitochondrial damage.3 More recently, Purdue et al4,5 and Nishiyama et al6 have precisely defined the molecular defect in this disease, further confirming that the primary abnormality is in AGT. In about 30% of patients with type 1 primary hyperoxaluria, a mutation exists which causes AGT, once synthesized, to be rerouted from its normal location in the peroxisome to the mitochondria (so-called targeting defect). These researchers have also mapped the genomic clone encoding AGT to
Small KW. Enzyme Deficiency for Type 1 Primary Hyperoxaluria. Arch Ophthalmol. 1992;110(1):13. doi:10.1001/archopht.1992.01080130015005