SINGLE-BASE DELETION IN EXON-7 OF THE GLYCOSYLASPARAGINASE GENE CAUSES A MILD FORM OF ASPARTYLGLYCOSAMINURIA IN A PATIENT OF MAURITIAN ORIGIN

Aspartylglycosaminuria (AGU) is a lysosomal storage disorder of glycop rotein degradation caused by deficiency of glycosylasparaginase (GA). A deletion mutation was found in a mildly affected AGU patient whose p arents are first-cousins of Mauritian origin. One bp deletion at posit ion 787 or 788 (Delta T-788) in exon 7 of the GA gene resulted in a fr ameshift and produced an immediate stop codon. The resulting truncated polypeptide was defective in its post-translational proteolytic proce ssing and remained as a single chain (36kDa) with no GA activity.