A study of the genetics of galactosaemia.

Abstract

SummaryGalactose‐1‐phosphate uridyltransferase has been determined, by a manometric method, in the lysed erythrocytes of galactosaemic children and their families and in normal controls. Parents of galactosaemic children have about 64 % of the enzyme activity found in controls, while homozygous individuals have little or none. There is a slight overlap of enzyme levels in the control and heterozygote groups. This renders a definite placing of borderline cases impossible.There is some evidence to suggest that the quantitative differences between heterozygotes are not indicative of different genotypes. The possible existence of different genetic variants, whose phenotypical expression is the same, have been discussed.We would like to record our gratitude to the Board of Governors, United Manchester Hospitals, for a maintenance grant to one of us (A.R. W.) and for defraying costs of reagents and other incidental expenses; to Profs. W. Gaisford and A. C. P. Campbell for their unfailing support; to Prof. Sir Robert Piatt and Prof. H. Harris for reading the manuscript and offering valuable advice; to Dr A. H. Gowenlock for assistance with the statistical evaluation of the results; and to many Paediatricians and Pathologists all over the British Isles for their co‐operation with us in securing specimens from their patients. We would also like to thank Mr E. G. Smith and the Department of Medical Illustration of the Manchester Royal Infirmary for the preparation of the illustrations.