Fibroblast alpha-galactosidase A activity for identification of Fabry's disease heterozygotes

The identification of female carriers of Fabry's disease is important for genetic counselling since prenatal diagnosis of affected fetuses is possible. The activities of either total alpha-galactosidase or alpha-galactosidase A in cultured fibroblasts were similar in Fabry carriers and controls and cannot therefore be used for carrier detection. Better discrimination between carriers and controls was found when total alpha-galactosidase activity was expressed as a ratio to beta-galactosidase activity, but overlap still occurred. However, there was complete discrimination between the ratio of alpha-galactosidase A to beta-galactosidase in cultured fibroblasts from five carriers of Fabry's disease and either 11 controls, seven hemizygote affected males or two of their female relatives.