A new polymorphism of arylsulfatase A within the coding region.
A 10-year-old boy with juvenile metachromatic leukodystrophy (MLD) presented with the 459 + 1G-->A arylsulfatase A (ASA) mutation on one allele. To detect his complete genotype, the other ASA allele was sequenced and a T-to-C transition at nucleotide 376 in exon 2 was identified. This missense mutation results in a substitution of leucine 76 by proline. Of 20 MLD unrelated controls, 18 carried the L/P76 mutation either in the homozygous (n = 6) or heterozygous (n = 12) state. The presence or absence of L/P76 did not influence leukocyte ASA activity or urinary sulfatide excretion. Apparently, the substitution of leucine 76 by proline is a common ASA polymorphism, neither being related to MLD nor creating ASA pseudodeficiency. However, because of its frequency and location, L/P76 may be of particular importance in genetic studies requiring the differentiation of the ASA alleles within a kindred. Further studies are directed to the as yet unresolved genotype of the index case with juvenile MLD.
Berger
J
J
Institute of Neurology, University of Vienna, Austria. Johannes.Berger@univie.ac.at
Gmach
M
M
Faé
I
I
Molzer
B
B
Bernheimer
H
H
D000483:Alleles; D001483:Base Sequence; D002553:Cerebroside-Sulfatase / Q000235:genetics*; D002648:Child; D017931:DNA Primers; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D007966:Leukodystrophy, Metachromatic / Q000235:genetics; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D011110:Polymorphism, Genetic
D017931:DNA Primers; D002553:Cerebroside-Sulfatase