The human growth hormone gene (
GH1) and the insulin-like growth factor 1 and 2 genes (
IGF1 and
IGF2) encode the central elements of a key pathway influencing growth in humans. This “growth pathway” also includes transcription
factors, agonists, antagonists, receptors, binding proteins, and endocrine factors that constitute an intrincate network of
feedback loops.
GH1 is evolutionarily coupled with other genes in linkage disequilibrium in 17q24.2, and the same applies to
IGF2 in 11p15.5. In contrast,
IGF1 in 12q22-24.1 is not in strong linkage disequilibrium with neighbouring genes. Knowledge of the functional architecture of
these regions is important for the understanding of the combined evolution and function of
GH1,
IGF2 and
IGF1 in relation to complex diseases. A number of mutations accounting for rare Mendelian disorders have been described in GH-IGF
elements. The constellation of genes in this key pathway contains potential candidates in a number of complex diseases, including
growth disorders, metabolic syndrome, diabetes (notably
IGF2BP2) cardiovascular disease, and central nervous system diseases, and in longevity, aging and cancer. We review these genes and
their associations with disease phenotypes, with special attention to metabolic risk traits.