Erythrocyte uridine diphosphate galactose-4-epimerase deficiency identified by newborn screening for galactosemia in the United States

Eight infants (two whites and six blacks) with erythrocyte uridine diphosphate galactose-4-epimerase (epimerase) deficiency were identified in four newborn screening programs for galactosemia in the United States. The initial biochemical findings in all cases were elevated blood galactose-l-phosphate with normal or only slightly increased blood galactose and normal galactose-l-phosphate uridyltransferase (GALT) activity. Epimerase deficiency was confirmed in erythrocytes by a two-step enzymatic assay involving fluorometric measurements of NADH generated by coupling the uridine diphosphate glucose dehydrogenase reaction to epimerase. Seven of the eight infants appeared to be clinically normal at birth and one newborn had neonatal jaundice. The infrequent recognition of epimerase deficiency is likely due to the methods of newborn screening for galactosemia which are often only for GALT deficiency and perhaps also due to incomplete follow-up of increased metabolite levels in newborn blood specimens with normal GALT activity. Our results confirm a preliminary report of a high frequency of erythrocyte epimerase deficiency in the American black population.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30522/1/0000153.pd