Prevalence of GSTM1 and GSTT1 null polymorphisms in an admixed healthy Venezuelan population: implications for pharmacogenetic baselines.

Introduction: The Glutathione S-Transferase (GST) family consists of enzymes with widely studied genetic polymorphisms. Current documentation of GST variant distribution across Venezuelan regions is fragmented. This study aims to determine the prevalence of GSTM1 and GSTT1 null genotypes in a healthy urban Venezuelan group and to compare these frequencies with regional and global reference data. Methods: A cross-sectional descriptive study was conducted on 300 healthy unrelated individuals. Genotyping was performed via multiplex PCR, and frequencies were calculated based on the presence or absence of specific amplicons. Results: The frequencies of the GSTM1 and GSTT1 null genotypes were 38.67% and 32.67%, respectively. The "double null" genotype was observed in 6.00% of the sample, representing a relevant ethnogeographic heterogeneity. Discussion: Comparative analysis revealed a divergence from reported data for ancestral Amerindian groups and an allelic distribution pattern reflecting a tri-hybrid genetic architecture intermediate between West African and Southern European references. These findings establish an updated genetic baseline for this urban cohort, highlighting a distinct genotypic distribution within the Venezuelan population. This study underscores the degree of population stratification in the region and provides a descriptive framework for future toxicogenomic research and personalized medicine applications.