Pathogenicity of novel GLA gene missense mutations in Fabry disease and the therapeutic impact of migalastat.
Background: Fabry disease, a rare X-linked hereditary lysosomal storage disorder caused by mutations in the GLA gene, affecting multiple organs. However, functional validation data on the pathogenicity of newly identified mutations and research on the effects of migalastat intervention at different mutation sites is lacking.
Objective: To explore the pathogenicity of newly identified missense mutations in the GLA gene in Fabry disease and the intervention effect of migalastat on the disease model of newly identified mutation sites.
Methods: We retrospectively screened newly identified mutations from the clinical data of 163 patients with Fabry disease, investigated the pathogenicity of these mutations by clinical data and pedigree analysis, bioinformatics prediction, protein structure modeling prediction, and cell experiment. Additionally, this study further assessed the effects of migalastat intervention on these newly identified mutation sites combined with the amenable mutation criteria for GLA gene mutations applicable to DGJ proposed by the Good Laboratory Practice Human Embryonic Kidney 293 in vitro cell experiment analysis (GLP HEK assay).
Results: Ninety-five different mutation sites were detected, comprising 13 newly identified mutation sites with nine definite pathogenic mutations (nonsense mutations, frameshift mutations and large fragment deletions) and four missense mutations. The variants c.102 T > A, c.130 T > G, and c.778G > T showed high pathogenicity (pathogenicity prediction score: 9), suggesting significant spatial conformation changes in the mutated protein, while c.194G > A showed a low pathogenicity (score: 5), indicating a mild impact on protein conformation. Cellular functional experiments revealed significantly reduced GLA gene mRNA, α-Gal A protein expression, and enzyme activity levels in the mutant cells. Migalastat intervention significantly normalized α-Gal A protein expression and enzyme activity, particularly in the variant c.194G > A, meeting amenable mutation criteria for migalastat.
Conclusions: This study reports 13 newly identified mutation sites in the GLA gene for Fabry disease, including nine definite pathogenic mutations and four missense mutations confirmed to be pathogenic in this study, thereby enriching the Fabry disease gene mutation database. Migalastat intervention improved enzyme activity in these mutation models, especially in cases with minor changes in protein structure and function, which are expected to guide clinical treatment.