The CK-MM NcoI AA genotype was associated with a sixfold higher risk of being a high responder for creatine kinase after exercise compared with GG and AG genotypes (P=0.031).
Observational (n=88)
Are CK-MM NcoI and ACE I/D polymorphisms associated with an extreme creatine kinase response to exercise?
The CK-MM AA genotype and percent body fat are associated with an extreme increase in blood CK after exercise, suggesting a mechanism for susceptibility to exertional rhabdomyolysis.
Relative Risk: 6
p-value: p=0.031
Exertional rhabdomyolysis (ERB) is a syndrome of severe skeletal muscle breakdown. Blood levels of creatine kinase (CK) are widely used as a marker to reflect muscle breakdown. Some individuals exhibit extreme increases in blood CK after exercise and have been characterized as high responders (HR), but no clinical definition of HR exists and reasons for the HR phenomenon are not understood. This study investigated possible associations between the magnitude of the CK response to exercise and polymorphisms of two genes: muscle-specific creatine kinase (CK-MM) NcoI and angiotensin-converting enzyme (ACE) I/D. An exercise test for defining HR was also investigated. Participants (n = 88) underwent an exercise test that included stepping up and down two stairs for 5 min followed by 15 squats while wearing a backpack weighted at 30% of their body weight. CK levels were measured before, immediately after, and 48 and 72 h after the test. Nine participants (10.2%) were defined as HR. Participants with the CK-MM NcoI AA genotype had a sixfold higher risk of being HR compared with GG and AG genotypes (P = 0.031). No significant differences were found for the ACE I/D polymorphism. Percent body fat was an independent predictor of being a HR. We conclude that the CK-MM AA genotype and percent body fat may be part of the constellation of mechanisms that explain susceptibility to ERB. A physiological test that may assist in predicting ERB is also presented.
Heled et al. (Fri,) conducted a observational in Exertional rhabdomyolysis susceptibility (n=88). CK-MM NcoI AA genotype vs. GG and AG genotypes was evaluated on High responder (HR) status for creatine kinase response to exercise (sixfold higher risk, p=0.031). The CK-MM NcoI AA genotype was associated with a sixfold higher risk of being a high responder for creatine kinase after exercise compared with GG and AG genotypes (P=0.031).