LINKAGE BETWEEN A MUSCLE-SPECIFIC CREATINE KINASE GENE POLYMORPHISM AND VO2MAX TRAINABILITY IN THE HERITAGE FAMILY STUDY

37 We reported (MSSE 29:S230, 1997) a significant association between a muscle specific creatine kinase (CKMM) gene polymorphism and VO2max response(Δ) to an endurance training program (MSSE 27:721-729, 1995). The purpose of this study was to test whether there was a genetic linkage between the CKMM marker and ΔVO2max. Linkage analysis using the sib-pair method was performed on 220 pairs of full siblings from 86 nuclear families of the HERITAGE Family Study. VO2max was measured during maximal stationary cycle ergometer tests before and after 20 weeks of endurance training. The CKMM polymorphism was detected by the polymerase chain reaction and digestion with the NcoI restriction enzyme. Frequencies for the rare (1170 base pairs; bp) and common (985 + 185 bp) alleles were 0.32 and 0.68, respectively. These alleles were shown to have a Mendelian mode of inheritance using familial data. After adjustment of ΔVO2max for the effects of age, sex, initial VO2max and body mass, the evidence of linkage between the CKMM locus and ΔVO2max was not impressive(P=0.049). However, in light of the small sample size, one may regard this as providing some support for the notion that the CKMM gene or a gene in close proximity may influence individual variation in the VO2max response to endurance training.