Identification a novel mononucleotide deletion mutation in GAA in pompe disease patients

Background: Mutations in the acid alpha?glucosidase ( GAA ) gene usually lead to reduced GAA activity. In this study, we analyzed the mutations of GAA and GAA enzyme activity from one sibling suspected Pompe disease and their frst?degree relatives. Materials and Methods: In this  cross?sectional study, GAA enzyme activity assay was assessed using tandem mass spectrometry. Polymerase chain reaction and Sanger sequencing were performed for GAA analysis. Results: GAA enzyme activity was signifcantly 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 been previously 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 the discovered deletion in the GAA might lead to a reduced activity of the gene product.