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Genetic study of the height and weight process during infancy
Paula van Dommelen1, Mathisca C M de Gunst, Aad W van der Vaart
1Department of Mathematics, Vrije Universiteit, Amsterdam, the Netherlands. P.vanDommelen@pg.tno.nl
Summary
Childhood growth parameters like height and weight are influenced by genetics and environment. Heritability plays a significant role in growth velocity and size at 1 and 2 years of age.
Area of Science:
- Human Growth and Development
- Quantitative Genetics
- Pediatrics
Background:
- Understanding the genetic and environmental influences on early childhood growth is crucial for identifying developmental trajectories.
- Twin studies are a powerful tool for disentangling heritability and environmental contributions to complex traits.
Purpose of the Study:
- To analyze longitudinal height and weight data from Dutch twin pairs from birth to 2.5 years of age.
- To decompose variation and covariation in growth curve parameters into genetic and non-genetic sources.
- To assess the influence of gestational age on early growth parameters.
Main Methods:
- Utilized a mixed-effects procedure to summarize longitudinal data into polynomial parameters (degree 4).
- Applied quantitative genetic models to decompose variance and covariation of growth parameters (size, velocity, deceleration, jerk, snap).
- Analyzed genetic and environmental influences on estimated size at birth and 2 years of age.
Main Results:
- Gestational age significantly impacted size at birth (39% of variance).
- Heritability was highest for size at 1 and 2 years, and weight growth velocity.
- Additive genetic factors explained substantial variance in height (52-58%) and weight (approx. 58%) at 2 years.
Conclusions:
- Early childhood growth is influenced by additive genetic, common environmental, and specific environmental factors.
- Heritability is a major determinant of growth velocity and attained size in early childhood.
- Specific growth parameters like snap and jerk show complex genetic and environmental influences, with some shared factors across sexes and parameters.