Los Angeles variant of galactose-1-phosphate uridyltransferase (EC 2.7.7.12) in a Mexican family.

Enzymatic activity and electrophoretic mobility of galactose-1-phosphate uridyltransferase (EC 2.7.7.12) were assayed in a Mexican family (8 sibs and their parents) with two galactosemic members. Normal, galactosemic and Los Angeles enzyme variants were identified. A survey of the ethnological backgrounds of the individuals reported to date with the Los Angeles variant showed multiple origins that could be explained by an ancient and widespread gene mutation or, more probably, by further biochemical heterogeneity.