Evaluation of the Bacillus subtilis inhibition-assay technic as a screening procedure for the detection of phenylketonuria.

RECENTLY Guthrie1 2 3 4 described a screening technic for the early diagnosis of phenylketonuria, utilizing the inhibiting property of beta-2-thienylalanine on the growth of Bacillus subtilis. This inhibiting phenomenon is specifically prevented by phenylalanine, proline and phenylpyruvic acid. By means of this inhibition test one is able to determine the presence of high levels of these substances in blood and other fluids. The Guthrie inhibition assay has been used successfully to determine blood phenylalanine levels in a group of 16 patients during treatment with diets low in phenylalanine and to screen a large population of retardates in a state school in . . .