Summary
A method is described for detecting the healthy heterozygote carriers of phenylketonuria, both for eugenic counseling and as a diagnostic aid in distinguishing typical from atypical phenylketonuria. The plasma phenylalanine/tyrosine molar ratio (which can be taken as an index of heterozygosity) was determined in a group of 60 proven heterozygotes for phenylketonuria and a group of 161 normal individuals. In the normal individuals sampled the phenylalanine/tyrosine molar ratio varied from 0.52 to 1.04, whereas in the heterozygotes it ranged from 1.08 to 1.98. There was no zone of overlap between the 2 groups. This was probably due to the high accuracy of the analytical method, which is based on a new automatic system for analysis of amino acids by ion-exchange chromatography that performs 4 phenylalanine/tyrosine determinations/h, and to the method of preparation and preservation of the sample to be analyzed, developed at the RBM laboratories.
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Mondino, A., Bongiovanni, G., Fumero, S. et al. The determination of heterozygosity for phenylketonuria. La Ricerca in Clin. Lab. 5, 329–339 (1975). https://doi.org/10.1007/BF02910157
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DOI: https://doi.org/10.1007/BF02910157