Submitted on May 19, 2008
Revised on July 29, 2008
Accepted on July 29, 2008
Genome-wide linkage scan for contraction velocity characteristics of knee musculature in the Leuven Genes for Muscular Strength Study
Gunther De Mars1, An Windelinckx1, Wim Huygens1, Maarten Wim Peeters1, Gaston P Beunen1, Jeroen Aerssens2, Robert Vlietinck3, and Martine AI Thomis1*
1 Research Center for Exercise and Health
2 TIBOTEC
3 KULeuven
* To whom correspondence should be addressed. E-mail: martine.thomis{at}faber.kuleuven.be.
The torque-velocity relationship is known to be affected by ageing, decreasing its protective role in the prevention of falls. Interindividual variability in this torque-velocity relationship is partly determined by genetic factors (h²: 44-67%) As a first attempt, this genome-wide linkage study aimed to identify chromosomal regions linked to the torque-velocity relationship of the knee flexors and extensors. A selection of 283 informative male siblings (17-36 years), belonging to 105 families, was used to conduct a genome-wide SNP-based (Illumina Linkage IVb panel) multipoint linkage analysis for the torque-velocity relationship of the knee flexors and extensors. The strongest evidence for linkage was found at 15q23 for the torque-velocity slope of the knee extensors (TVSE). Other interesting linkage regions with LOD scores > 2 were found at 7p12.3 (LOD = 2.03; P = 0.0011) for the torque-velocity ratio of the knee flexors (TVRF), at 2q14.3 (LOD = 2.25; P = 0.0006) for TVSE, and at 4p14 and 18q23 for the torque-velocity ratio of the knee extensors TVRE, (LOD = 2.23 and 2.08; P = 0.0007 and 0.001, respectively). We conclude that many small contributing genes are involved in causing variation in the torque-velocity relationship of the knee flexor and extensor muscles. Several earlier reported candidate genes for muscle strength and muscle mass and new candidates are harboured within or in close vicinity of the linkage regions reported in the present study.
