Enzymatic abnormality of the carrier state in metachromatic leukodystrophy.

Abstract Arylsulfatase A activity in leukocytes from patients and from their close relatives was investigated in three families with metachromatic leukodystrophy. The activity of arylsulfatase A in leukocytes from three patients with metachromatic leukodystrophy was approximately one tenth of the mean control value. The enzyme activity in leukocytes from the parents of affected patients and from some of their relatives was approximately half that found in control subjects, demonstrating a gene-dose effect. There appeared to be no overlap between the enzyme activities in leukocytes from the parents of patients and from normal individuals. These findings suggest that the heterozygous carrier state in metachromatic leukodystrophy could be predicted by the assay of arylsulfatase A in leukocytes and autosomal recessive mode of inheritance may be assumed.