Fabry's disease: normal α-galactosidase activity and urinary-sediment glycosphingolipid levels in two obligate heterozygotes

A clinical and hiochemical study of twelve persons in the same family, including two hemizygous and one typical heterozygous patients, for Fabry's disease is reported. Two obligate heterozygous females—daughters of the index case—lacked any of the clinical manifestations found in typical heterozygous carriers, having also normal α‐galactosidase activity in peripheral leukocytes and normal urinary excretion of trihexosylceramide and digalactosylceramide. Blood group serology was determined to exclude illegitimacy. The validity of these findings and some possible explanations are discussed.