STUDIES ON LEUKOCYTE BRANCHER ENZYME ACTIVITY IN A FAMILY WITH TYPE 4 GLYCOGENOSIS

Brancher enzyme activity was measured with extracts of leukocytes from the parents of a child who died with type IV glycogen storage disease. The activity of this enzyme was reduced to approximately half that of leukocyte extracts from control patients, demonstrating a gene-dose effect. These findings tend to confirm deficiency of brancher enzyme activity as the primary defect and also suggest an autosomal recessive mechanism of inheritance of this disorder. Type IV glycogenosis is one of some 20 inborn metabolic disorders in which study of leukocytes can serve to identify the homozygous deficient or the heterozygous individual. © 1969 The C. V. Mosby Company.