Association Between CKMM Genotype and Endurance Performance Level in Hispanic Marathon Runners

1775 PURPOSE: We examined the association between a genetic polymorphism at the muscle-specific creatine kinase (CKMM) locus and endurance performance level (EPL) status. METHODS: DNA samples were successfully genotyped from 203 Hispanic marathon runners (men n = 157; women n = 46). Cases (n = 101; men = 77; women = 24) were finishers in the top 3%, while controls (n = 102; men = 80; women = 22) were those in the lowest 3% of their respective age and category. Genotypes were determined by PCR and digestion with NcoI endonuclease. RESULTS: The three expected genotypes for the CKMM-NcoI were observed in the cases and controls. These genotypes frequencies were in Hardy-Weinberg equilibrium (χ2, P>0.05) and were not significantly (χ2, P>0.05) different between genders. Moreover, the allelic frequencies did not differed (P>0.05) between genders. The pooled data for both genders revealed no significant differences in genotype (P>0.05) or allele (P>0.05) frequencies between the cases and controls. CONCLUSION: These results reinforce the findings of a previous study in Caucasians (MSSE 29:1444, 1997) and suggest that the CKMM-NcoI polymorphism is not likely an important determinant of endurance performance level. Supported by CRC-RCMI 1P20RR11126, RCMI #G12RR03051, Comité de Fondismo: FPRA, Maratón Pacifico, Maratón de Culiacán, Maratón de Guadalajara, Maratón Popular de Madrid.