Low arylsulphatase A activity in a family without metachromatic leukodystrophy

Abstract

A low arylsulfatase A activity was noted in the leukocytes and cultured skin fibroblasts of a child without any other symptoms of metachromatic leukodystrophy. Although the mother had a level of arylsulfatase A commensurate with heterozygosity for the classical metachromatic leukodystrophy gene, the father had a variant gene giving an unusually low in vitro level of this enzyme. These 2 genes gave rise to a very low in vitro activity without any apparent disease in the proband. In screening for metachromatic leukodystrophy, a low arylsulfatase A level is not necessarily indicative of this disease, if a clinically normal parent shows an unusually low level of this enzyme.