ARYLSULFATASE-A - RELATIONSHIP OF GENOTYPE TO VARIANT ELECTROPHORETICPROPERTIES

Previous work has shown that specific electrophoretic variants of aryl sulfatase A occur more frequently among alcoholic patients than among psychiatric and normal controls. The present study sequenced the gene for two of these electrophoretic variants, IIIa and IIIb. Both contain an A-to-G transition corresponding to substitution of Asn(350) by Ser , with the resulting loss of an N-glycosylation site. The difference i n electrophoretic mobility of their gene products is due to a mutation in the IIIb gene resulting in the replacement of Arg(496) by His. Evi dence is presented that individuals possessing either of two other ele ctrophoretic variants, Va and Vb, are heterozygous for a normal ASA al lele and either a IIIa or IIIb allele, respectively. Thus, the relatio nship between the phenotype of the electrophoretic banding patterns, I IIa, IIIb, Va, and Vb, and their corresponding genotypes has been eluc idated.