alpha-L-iduronidase activity in leukocytes: diagnosis of homozygotes and heterozygotes of the Hurler syndrome.

The activity of alpha-L-iduronidase was determined in leukocytes from two patients with the Hurler syndrome, five obligatory heterozygotes, one patient with the Hunter syndrome, and ten normal individuals. It was found that the determination of alpha-L-iduronidase in leukocytes was a useful method for differential diagnosis between the Hurler and Hunter syndromes. Heterozygotes of the Hurler syndrome showed approximately 50% level of alpha-L-iduronidase activity in leukocytes as compared with that of normal individuals. This suggests that the determination of alpha-L-iduronidase activity may be available for the carrier detection of the Hurler syndrome.