From midlife on, muscle strength declines, approximately one percent annually. This decline may eventually predispose people to mobility limitation, falls and bone fractures. Individual differences in muscle phenotypes in old age may be explained by both environmental and genetic factors2.
The Finnish Twin Study on Aging (FITSA)1, examined whether polymorphisms within COMT and ESR1 were associated with muscle properties and assessed their interaction and their combined effects with physical activity. The results indicated that the COMT polymorphism, affecting the activity of the enzyme, is associated with muscle mass. Furthermore, sedentary individuals with potential high enzyme activity were the weakest group, but they may potentially benefit the most from physical activity. This observation elucidates the importance of both environmental and genetic factors in muscle properties.
The COMT gene provides instructions for making an enzyme called catechol-O-methyltransferase. This enzyme helps maintain levels of neurotransmitters like: epinephrine, norepinephrine and dopamine. COMT-controlled methylation reactions help prevent DNA damage from oxidative stress.5
A functional G to A polymorphism in the rs4680 COMT gene results in a valine to methionine amino acid transition (COMT Val158Met polymorphism) leading to lower activity of the enzyme3. This could increase the availability of estrogen and induce the anabolic effects of this hormone on target tissues such as skeletal muscle.
Related to:
ESR1, postmenopausal women