Introduction

This chapter provides an overview of the methods currently available to study the genetic epidemiology of normal human growth and development. Over the past two decades numerous technological innovations have enabled researchers to investigate issues that were here to fore intractable. These innovations include the advent of relatively low-cost yet powerful computers, the development of sophisticated statistical genetic modelling approaches, and advances in high-throughput genotyping. Progress in these areas has allowed for more through genetic investigations of complex traits such as those comprising growth and development. These investigations not only assess the degree of genetic control of a trait, but also identify genes influencing variation in them.

A number of general points can be made regarding past research on the inheritance of growth-related traits. First, almost all studies to date have established that human growth is at least partly influenced by genes. These studies have examined familial resemblance of various growth and development measures including stature, weight and various maturational indicators (e.g. age at menarche, pubertal stage or skeletal age). Estimates of the proportion of variance attributable to the effects of genes (i.e. heritability) vary according to the trait of interest. Stature is among the most highly heritable of growth measures with estimates ranging as high as 0.92, indicating that as much as 92% of the total variation in stature can be attributable to the effects of genes (Wilson, 1976; Kaur and Singh, 1981).