Polymorphism of human galactose-1-phosphate uridyl transferase.

Frequencies for the electrophoretically detectable alleles of galactose-1-phosphate uridyl transferase were determined from 406 neonates in Adelaide. GALTD and GALTLA frequencies were 0.054 and 0.027, respectively. The expected proportion of heterozygotes was 15.3%, with a GALT N-D component of 10%. The distinction between GALTD and GALTLA is essential for estimation of the expected frequency of GALT DG genotypes, an unknown proportion of which are detected as 'deficient' from neonates on galactosaemia screen.