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Related Experiment Video

Updated: Jun 15, 2026

Tissue Triage and Freezing for Models of Skeletal Muscle Disease

Tissue Triage and Freezing for Models of Skeletal Muscle Disease

Published on: July 15, 2014

ACTN3 polymorphism affects thigh muscle area.

H Zempo¹, K Tanabe, H Murakami

¹Sports Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tennodai, Tsukuba, Japan.

International Journal of Sports Medicine

|March 12, 2010

Summary

This summary is machine-generated.

The alpha-actinin-3 (ACTN3) R577X gene variant influences muscle mass in older Japanese women. Specifically, the XX genotype was associated with reduced thigh muscle size compared to other genotypes.

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Area of Science:

Genetics
Gerontology
Sports Medicine

Background:

Muscle mass is crucial for maintaining daily activities in older adults.
The alpha-actinin-3 (ACTN3) gene, particularly the R577X polymorphism, is known to affect muscle function.
Understanding genetic influences on muscle mass is vital for healthy aging strategies.

Purpose of the Study:

To investigate the association between the ACTN3 R577X gene polymorphism and muscle mass in older Japanese women.
To determine if genetic variations in ACTN3 impact thigh muscle cross-sectional area (CSA).
To explore the role of ACTN3 genotype in relation to physical activity and protein intake.

Main Methods:

Genotyping of 109 older Japanese women (mean age 64.1 years) for the ACTN3 R577X polymorphism.
Assessment of mid-thigh muscle cross-sectional area (CSA) using Magnetic Resonance Imaging (MRI).
Statistical analysis using analysis of covariance (ANCOVA) adjusted for body weight, comparing CSA among genotypes. Physical activity and protein intake were also measured.

Main Results:

The distribution of ACTN3 genotypes was RR (19%), RX (63%), and XX (27%).
No significant differences in physical activity or protein intake were found across the different ACTN3 genotypes.
Individuals with the ACTN3 XX genotype exhibited significantly lower thigh muscle CSA compared to those with the RR and RX genotypes (p<0.05).

Conclusions:

The ACTN3 R577X polymorphism is a significant factor influencing skeletal muscle mass in older Japanese women.
The XX genotype of ACTN3 is associated with reduced muscle mass, potentially impacting functional capacity in aging.
These findings highlight the importance of genetic predispositions in muscle health among the elderly Japanese population.