Novel deletion mutation in GAA in Iranian glycogen storage disease type II patients

Introduction: Pompe disease (PD) or glycogen storage disease type II is known as a rare progressiveneuromuscular disease in glucogenolis pathway characterized by the involvement of skeletal and cardiacmuscles. Alteration in the acid alpha-glucosidase (GAA) gene usually result to reduced enzyme GAA activity. Inpresent study, we investigate the mutations of GAA and enzyme GAA activity from two patients with PD andtheir first-degree relatives.Materials and Methods: In our cross-sectional study, GAA enzyme activity assay was assessed using tandemmass spectrometry. Polymerase chain reaction and Sanger sequencing were performed for GAA analysis.Results: GAA enzyme activity was significantly decreased in patients compared to the normal range (P = 0.02).Two individuals showed ten alterations in the GAA sequence, in which one of them (c. 1650del G) has not beenpreviously described in the literature. A single Guanine deletion (del-G) was detected at codon 551 in exon 12.Conclusion: According to the literature, the detected change is a novel mutation. We hypothesized that thediscovered deletion in the GAA might lead to a reduced activity of the gene product and is in agreement withbiochemical findings.

Keywords:

Acid alpha-glucosidase , Alteration , Polymerase chain reaction , Pompe disease