Biochemical genetics of glycogenosis type II in Brahman cattle.

Glycogenosis type II is an inherited lysosomal storage disorder caused by acid alpha-glucosidase deficiency. The disorder is inbred in Brahman cattle, and the incidence of carriers in Australian herds averages 15%. Affected animals are lethargic and die typically in the eighth or ninth month after birth. A complete lack of acid alpha-glucosidase synthesis was demonstrated in cultured fibroblasts and muscle tissue of affected animals. Moreover, the tissue was found to be devoid of acid alpha-glucosidase mRNA. Gross abnormalities of the acid alpha-glucosidase gene itself were not detected by Southern blot analysis. These results suggest Brahman glycogenosis type II to be caused by a point mutation or a micro deletion/insertion in the acid alpha-glucosidase gene.