ARYLSULFATASE-A PSEUDODEFICIENCY - INCIDENCE IN POLAND

Arylsulfatase A (ASA) pseudodeficiency (Pd) was defined as the in vitr o measurement of low enzyme activity in a healthy person. A variable i ncidence of the Pd allele was found in different populations; it was 1 0-20 times higher than that of metachromatic leukodystrophy (MLD). In Poland we estimated the incidence of the Pd allele at 6% and that of i solated 1788 mutation (loss of glycosylation site) at 3%. Out of 8 cas es with neurological symptoms and low ASA activity, 2 were found to be homozygous for the Pd allele; 2 MLD patients had healthy siblings hom ozygous for the Pd allele and another patient's allele bore two mutati ons, Pd and that causing MLD.