Characterization of two arylsulfatase A missense mutations D335V and T274M causing late infantile metachromatic leukodystrophy

✍ Scribed by Barbara Hess; Sabine Kafert; Uwe Heinisch; David A. Wenger; Joel Zlotogora; Volkmar Gieselmann

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 607 KB
• Volume: 7
• Category: Article
• ISSN: 1059-7794
• DOI: 10.1002/(sici)1098-1004(1996)7:4<311::aid-humu4>3.0.co;2-b

✦ Synopsis

Communicated by Leenu Peltonen

Metachromatic leukodystrophy is a lysosomal storage disorder caused by the deficiency of arylsulfatase A. We describe a novel missense mutation in exon 6 causing the substitution of Asp335 by Val. In transient transfections no enzyme activity could be expressed from the arylsulfatase A cDNA carrying this mutation. Examination of the effects of the mutation in cells stably overexpressing the mutant enzyme revealed, that the mutant enzyme is catalytically inactive and degraded in an early biosynthetic compartment. We have also investigated the effects of a previously identified mutation (T274M). The specific catalytic activity of the Met274 substituted arylsulfatase is reduced to about 35% of the normal enzyme when measured with an artificial substrate. Most of this enzyme is also degraded in an early biosynthetic compartment.