Genetic studies in galactosemia. I. The oral galactose tolerance test and the heterozygous state.

Response to oral administration of galactose, with dosage related to body surface, has been examined in 39 members of 13 families in which galactosemia has occurred. Genetic analysis of the families indicates an autosomal recessive mode of transmission of the defect. The finding of decreased tolerance to galactose in groups of parents and siblings is consistent with this analysis. Controls are included. The oral galactose tolerance test is not considered suitable for detection of an individual galactosemia carrier. The range of values of normals and heterozygotes overlap. Specific enzymatic methods may be more applicable.