A new mass screening method of detecting UDP-galactose-4-epimerase deficiency

A new mass screening method for detecting UDP-galactose-4-epimerase deficiency in newborn infants was devised so as to make a useful addition to the Guthrie test. Like Beutler's method, this method enables one to perform convenient spot tests on the basis of fluorometry of NADH. The preferred procedure was determined to be as follows: To a mixture of 10 microliter of 5-10 mM UDP-galactose, 10 microliter of 26 mM NAD, 10 microliter of a 1 M tris-HCl buffer (pH 8.0) and 10 microliter of a 1/100 dilution of a 5 mg/ml UDP-glucose dehydrogenase stock solution, distilled water is added until the total volume reaches 100 microliter. Then a blood-bearing filter paper disc is added to the mixture and, the reaction mixture is incubated at 37 degrees C for 6-17 hr. The resulting test solution is spotted on a Whatman No. 1 filter paper with a capillary tube, air-dried and tested for fluorescence with an ultraviolet light detector. No cases of UDP-galactose-4-epimerase deficiency were found in the present study.