Evidence for a founder effect in Sicilian patients with glycogen storage disease type II

Glycogen storage disease type II (GSD II) is an autosomal recessive inherit ed disorder due to the deficiency of the enzyme acid alpha-glucosidase, whi ch causes an accumulation of glycogen in lysosomes. The deletion of exon 18 (Delta 18) is a frequent mutation associated with a severe phenotype. We a nalyzed 25 Italian patients, 5 of whom were found to be Delta 18 carriers. AII these 5 patients came from Catania, a town in Sicily, We report on the analysis of 5 intragenic single-point polymorphic markers in the Delta 18 p atients and on the subsequent characterization of a Delta 18-associated hap lotype, The frequency of this haplotype in GSD II patients and normal indiv iduals was 1 and 0.196, respectively (chi(2) = 20.9; p < 0.001). The high f requency of the Delta 18 allele in this Italian subpopulation is likely to be due to a founder effect. Copyright (C) 2000 S. Karger AG, Basel.