Relationship between alpha-L-fucosidase deficiency in plasma and alpha-L-fucosidase activity in leukocytes

After testing a population sample of 185 hospitalized Italian children for the plasma alpha-L-fucosidase deficiency and establishing an approximate threshold value between heterozygotes and wild-type homozygotes, we analyzed by two statistical methods the distribution of the two genotypes. The results obtained by probit analysis agree with threshold and average values expected on the basis of the Hardy-Weinberg equilibrium. In addition, the level of alpha-fucosidase in leukocytes of 12 individuals with deficiency of alpha-fucosidase in plasma was found to be significantly lower than that of 61 controls (P less than 0.005). These results indicate that the mutation(s) causing a deficiency of alpha-fucosidase in plasma is (are) also expressed in leukocytes.