Relationship between serum growth hormone binding protein levels and height in young men

Novel genetic cause of idiopathic short stature

Traditionally, the growth hormone - insulin-like growth factor I (GH - IGF-I) axis is the most important signaling pathway in linear growth, and defects in this axis present as growth hormone deficiencies or IGF-I deficiencies. However, subtle changes in serum levels of GH or IGF-I, caused by gene mutations involved in the GH - IGF-I axis, can present as idiopathic short stature (ISS). This paper briefly discusses GHR and IGFALS. In addition, recent studies have shown that many factors, including paracrine signals, extracellular matrix, and intracellular mechanisms of chondrocytes, regulate the growth plate independent of the GH - IGF-I system. Rapid development of diagnostic technologies has enabled discovery of many genetic causes of ISS. This paper discusses 5 genes, SHOX, NPR2, NPPC, FGFR3, and ACAN, that may lead to better understanding of ISS.

Short and tall stature: a new paradigm emerges

In the past, the growth hormone (GH)-insulin-like growth factor 1 (IGF-1) axis was often considered to be the main system that regulated childhood growth and, therefore, determined short stature and tall stature. However, findings have now revealed that the GH-IGF-1 axis is just one of many regulatory systems that control chondrogenesis in the growth plate, which is the biological process that drives height gain. Consequently, normal growth in children depends not only on GH and IGF-1 but also on multiple hormones, paracrine factors, extracellular matrix molecules and intracellular proteins that regulate the activity of growth plate chondrocytes. Mutations in the genes that encode many of these local proteins cause short stature or tall stature. Similarly, genome-wide association studies have revealed that the normal variation in height seems to be largely due to genes outside the GH-IGF-1 axis that affect growth at the growth plate through a wide variety of mechanisms. These findings point to a new conceptual framework for understanding short and tall stature that is centred not on two particular hormones but rather on the growth plate, which is the structure responsible for height gain.