Identification and Characterization of a Novel Mutation c.1090G>T (G325W) and Nine Common Mutant Alleles Leading to Gaucher Disease in Spanish Patients

Background. Gaucher disease is an autosomal recessive disorder resulting from mutations in the glucocerebrosidase gene (GBA). The lack of full genotype/phenotype correlation complicates counseling regarding clinical outcome and treatment recommendations. Subjects and methods. Several mutations in the human β-glucosidase gene associated with Gaucher disease in 16 Spanish families were identified utilizing a combination of methods: enzymatic restriction, PCR–SSCP, and sequence analyses. Expression studies were performed following the introduction of the mutagenized human acid β-glucosidase cDNA into COS-1 cells, and the residual enzyme activities of the mutant protein were measured and compared with the normal cDNA. Results. The identified mutations and corresponding residual enzyme activities of the expressed protein are as follows: c.517A>C (T134P), 1%; c.721G>A (G202R), 17%; c.1090G>T (G325W), 13.9%; c.1093G>A (E326K), 26%; c.1208G>A (S364N), 4.1%; c.1226A>G (N370S), 17,8%; c.1246G>A (G377S), 17.6%; c.1289C>T (P391L), 8.5%; c.1448T>C (L444P), 3%; and c.1504C>T (R463C), 24.5%. Conclusions. Site-directed mutagenesis and expression in COS-1 cells are useful methods to increase our understanding of causality in Gaucher disease and the correlation between disease severity, gene defects, and residual enzyme activity. Our study demonstrates the functional consequences of the identified human β-glucosidase mutations (T134P, S364N, G377S, P391L, and G325W) and provide evidence for the molecular and biochemical basis of Gaucher disease, among patients of Spanish ancestry.