Novel mutations associated with metachromatic leukodystrophy: phenotype and expression studies in nine Czech and Slovak patients.
Metachromatic leukodystrophy (MLD) is an inherited demyelinating disorder caused by the deficiency of arylsulphatase A (ASA). This defect leads to an accumulation of galactosylceramide I(3)-sulphates (sulphatides) in lysosomes of different tissues. We report on mutations found in a group of nine patients from the Czech and Slovak Republics (former Czechoslovakia). Their diagnosis was confirmed by determination of the activity of arylsulphatase A in leukocytes and by abnormal urinary excretion of sulphatides. All alleles of the patients were identified and eight different mutations were found. They include four novel missense mutations in one infantile (D29N), one juvenile (C294Y), and three adult (C156R, G293S) patients. Four mutations were previously described sequence alterations (459 + 1G > A, G309S, I179S, and P426L). Polymorphisms characteristic for the ASA pseudodeficiency allele were not found in the patients. Substitutions of D29N, C294Y, and G293S in arylsulphatase A caused a severe reduction of enzyme activity in transient expression studies. In contrast, the C156R substitution reduces arylsulphatase A only to 50% of wild type ASA activity. Since no other mutations were found in this patient, the contribution of this mutation to the development of disease remains unclear.
Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague, Czech Republic.
Linda
L
Berná
Volkmar
V
Gieselmann
Helena
H
Poupetová
Martin
M
Hrebícek
Milan
M
Elleder
Jana
J
Ledvinová
D000293:Adolescent; D000328:Adult; D002478:Cells, Cultured; D002553:Cerebroside-Sulfatase / Q000235:genetics / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D018153:Czech Republic; D017931:DNA Primers; D005260:Female; D005838:Genotype; D006801:Humans; D007223:Infant; D007962:Leukocytes / Q000378:metabolism; D007966:Leukodystrophy, Metachromatic / Q000235:genetics*; D008297:Male; D016296:Mutagenesis; D009154:Mutation / Q000235:genetics*; D010641:Phenotype; D017422:Sequence Analysis, DNA; D018154:Slovakia; D013433:Sulfoglycosphingolipids / Q000652:urine; D014162:Transfection
D017931:DNA Primers; D013433:Sulfoglycosphingolipids; D002553:Cerebroside-Sulfatase