Molecular genetic analysis of Turkish Gaucher's disease patients reveals three novel variants in Glucocerebrosidase (GBA) gene

Abstract

Gaucher's disease (GD) is the most prevalent lysosomal storage disorder caused by the deficiency of β-glucosylceramidase enzyme (EC 3.2.1.45) due to mutations in the GBA gene. To date, more than 400 GBA mutations have been described. In this study, we aim to summarize the clinical and molecular genetic background of Turkish GD patients. 114 GD patients from 95 families from various regions of Turkey were enrolled in this study. GBA mutations were screened by hybridization-based strip assay and/or DNA sequencing methods. The possible effects of the novel GBA mutations on the β-glucosylceramidase enzyme were analyzed by in silico mutation prediction and protein modeling tools. We identified 75 GD patients with homozygous and 39 GD patients with compound heterozygous GBA mutations. 54% of all patients were clinically diagnosed as GD TypeI, 30% as GD TypeIII, and 5% as GD TypeII. Approximately 6% of the patients diagnosed as either TypeI or TypeIII due to the early age at diagnosis (6–24 months) and a short-term follow up. This study revealed 24 different GBA mutations in 186 mutant alleles. In Turkish GD cohort, the most common GBA mutations were p.L483P (38.8%), p.N409S (32.6%), p.D448H (8.9%), and p.L335V (3.1%). Here, we also report one missense and two frameshift mutations (p.S405T, p.L135Vfs*10, and p.F186Sfs*14) not previously reported in GD patients. Our results help to identify the mutational spectrum of theGBA gene in Turkish GD patients and reveal possible impacts of the molecular genetic data on the clinical outcomes in terms of the genotype-phenotype correlation.