Twin Research and Human Genetics

Articles

Genetics of Maximal Walking Speed and Skeletal Muscle Characteristics in Older Women

Kristina M. Tiainena1 c1, Markus Perolaa2, Vuokko M. Kovanena3, Sarianna Sipiläa4, Katja A. Tuononena5, Kaisa Rikalainena6, Markku A. Kauppinena7, Elisabeth I.M. Widena8, Jaakko Kaprioa9, Taina Rantanena10 and Urho M. Kujalaa11

a1 The Finnish Centre for Interdisciplinary Gerontology, Department of Health Sciences, University of Jyväskylä, Finland. kristina.tiainen@sport.jyu.fi

a2 Department of Molecular Medicine, National Public Health Institute, Helsinki, Finland; Department of Medical Genetics, University of Helsinki, Finland.

a3 Department of Health Sciences, University of Jyväskylä, Finland.

a4 The Finnish Centre for Interdisciplinary Gerontology, Department of Health Sciences, University of Jyväskylä, Finland.

a5 Department of Molecular Medicine, National Public Health Institute, Helsinki, Finland.

a6 Department of Biological and Environmental Sciences, University of Jyväskylä, Finland.

a7 The Finnish Centre for Interdisciplinary Gerontology, Department of Health Sciences, University of Jyväskylä, Finland.

a8 Finnish Genome Center, University of Helsinki, Finland.

a9 Department of Public Health, University of Helsinki, Finland; Department of Mental Health and Alcohol Research, National Public Health Institute, Helsinki, Finland.

a10 The Finnish Centre for Interdisciplinary Gerontology, Department of Health Sciences, University of Jyväskylä, Finland.

a11 Department of Health Sciences, University of Jyväskylä, Finland.

Abstract

The aim of this study was to examine whether maximal walking speed, maximal isometric muscle strength, leg extensor power and lower leg muscle cross-sectional area (CSA) shared a genetic effect in common. In addition, we wanted to identify the chromosomal areas linked to maximal walking speed and these muscle characteristics and also investigate whether maximal walking speed and these three skeletal muscle characteristics are regulated by the same chromosomal areas. We studied 217 monozygotic (MZ) and dizygotic (DZ) female twin pairs aged 66 to 75 years in the Finnish Twin Study on Aging study. The DZ pairs (94) were genotyped for 397 microsatellite markers in 22 autosomes and X-chromosome. Genetic modeling showed that, muscle CSA, strength, power and walking speed shared a genetic effect in common which accounted for 7% of the variation in CSA, 51% in strength, 37% in power and 35% in walking speed. The results of an explorative multipoint linkage analysis suggested that the highest LOD score found for each phenotype was 2.41 for walking speed on chromosome 13q22.1, 2.14 for strength on chromosome 15q14, 2.84 for power on chromosome 8q24.23, and 2.93 for muscle CSA on chromosome 20q13.31. Also a suggestive LOD score, 2.68, for muscle CSA was found on chromosome 9q34.3. The chromosomal areas of a suggestive linkage for strength and power partly overlapped LOD scores higher than 1.0 being seen for these phenotypes on chromosome 15. The present study was the first genome-wide linkage analysis to be conducted for these multifactorial and clinically important phenotypes underlying functional independence in older women.

(Received October 11 2007)

(Accepted February 11 2008)

Correspondence:

c1 Address for correspondence: Kristina Tiainen, Department of Health Sciences, University of Jyväskylä, The Finnish Centre for Interdisciplinary Gerontology, P.O. Box 35 (Viveca), FI-40014 University of Jyväskylä, Finland.

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