Genetic regulation of body size and morphology from adolescence to early adulthood

We analyzed the shared genetic background of extensive anthropometric measurements, determining body size and morphology.

Anthropometric measurements were taken for 15 traits from 1512 US twins at an average age of 11.7 years (Minnesota, 51% females) and for 20 traits at an average age of 14.8 years for males (N = 624) and 18.1 years for females (N = 505). Genetic twin modeling was utilized to estimate the genetic correlations between these traits.

In mid to late adolescence, high genetic correlations were found within height-related traits and foot length (r_A = 0.58-1.00) as well as within adiposity-related traits (r_A = 0.70-0.96), except for skinfold thicknesses. Genetic correlations for craniofacial measurements were smaller (r_A=0.26-0.80). However, almost all traits showed some genetic correlations with other traits, most of which were at least moderate (r_A > 0.30). Results from earlier assessments in early adolescence with fewer traits but a larger sample size were largely similar. Genetic correlations between the initial and follow-up assessments were high (r_A = 0.68-0.95), except for craniofacial traits, which showed somewhat lower correlations (r_A = 0.40-0.87).

Shared genetic variation plays a significant role in human body size and morphology as well as their development during adolescence.

There are clusters of anthropometric traits showing high genetic correlations. The highest genetic correlations were found within height- and adiposity-related traits. Nearly all anthropometric traits share some genetic variation. Genetic factors importantly contribute to the growth of all traits during adolescence. Pleiotropic effects are important for understanding the genetic regulation of human physique.