Metachromatic leukodystrophy: identification of the first deletion in exon 1 and of nine novel point mutations in the arylsulfatase A gene.

Metachromatic leukodystrophy (MLD), a lysosomal storage disease caused by the deficiency of arylsulfatase A (ASA), is inherited as an autosomal recessive trait, and its frequency is estimated to be 1 in 40,000 live births. Genomic DNA from 21 MLD patients (14 late-infantile and 7 juvenile cases) was amplified in four overlapping PCR fragments and tested by allele-specific oligonucleotide (ASO) for the two common mutations 459 + 1G-->A and P426L. These mutations were found in only 28.