Genetic variance of adolescent growth in stature

The aim of this study is to quantify the genetic and environmental variatio n in biological parameters of the adolescent growth in stature in both sexe s, using structural equation models. Standing height was measured in 99 twi n pairs from the Leuven Longitudinal Twin Study. Subjects were seen at semi -annual intervals between 10 and 16 years and at is years. Preece-Baines mo del I was fitted to the individual data and biologically meaningful paramet ers were derived. Path models were fitted to these parameters and a gender heterogeneity analysis was performed. A model including additive genetic an d specific environmental factors (AE-model), allowing for a difference in t otal variance or in genetic/environmental variance components in males and females best explains most of the growth characteristics. For the timing an d velocity of the adolescent growth spurt, no gender heterogeneity was obse rved, and the genetic (0.89 to 0.93) and specific environmental (0.07 to 0. 11) contributions were equal in bath sexes. For stature at take-off, statur e at peak height velocity and for adult stature, gender heterogeneity was o bserved and different models appeared to result in the best fit for boys an d girls. For height at PHV and adult stature, the significant contribution of a common environmental (0.39 to 0.56) factor in boys was noteworthy. For percentage of adult stature and distances between relevant time points of the growth curve, a non-scalar effect was observed, indicating that differe nt genes affect these characteristics in boys and girls. It is concluded th at most characteristics of the growth spurt in stature are under strong gen etic control. Gender heterogeneity is present for stature and for a number of derived growth characteristics.