Genetic contribution to variation in body configuration in Belgian nuclear families: a closer look at body lengths and circumferences.

The purpose of the current study was to evaluate the contribution of genetic factors on body configuration related phenotypes. The sample consisted of 119 Belgian nuclear families including 231 males and 229 females. Factor analysis with varimax rotation was carried out to analyse 13 length and circumference measures and the resulting two synthetic traits (LF and CF; linear and circumference factors, respectively) were used as summary variables. Univariate quantitative genetic analysis indicated that variation in anthropometric as well as in synthetic traits was significantly dependent on additive genetic effects, with heritabilities ranging from 0.55 to 0.88. Narrow sense heritability estimates were higher for measurements principally characterizing skeletal mass than in variables that also involve soft-tissues. Sex, age and their interactions explained 11-67% of the total phenotypic variance. This report also examined the covariations between pairs of anthropometric and synthetic traits (length measurements and LF vs. height; circumference measures and CF vs. weight and BMI; LF vs. CF). Significant genetic correlations among all the studied traits (except for middle finger length vs. height) confirmed the influence of pleiotropy on genetic determination of these phenotypes. Bivariate analysis showed that pleiotropic effects had a great influence in determining body traits variation within body length measurements, as well as between body circumferences and weight or BMI. In relation to the two synthetic traits, even the variation of body lengths and circumferences was highly determined by genetic factors, shared genetic influences were unlikely to explain much of the observed variation between LF and CF. The results of the present study allow us to conclude that in this population body configuration related traits are subject to a strong genetic control and that shared genes also contribute to this genetic structure.