The pygmy short stature enigma.

The Pigmy populations of Central Africa are known as the shortest human populations worldwide showing an endocrine profile similar to Caucasian individuals with idiopathic short stature. Therefore, the study of these subjects may significantly improve our knowledge of the mechanisms regulating normal growth in humans. In this review we summarize the existing knowledge on Pygmies' short stature, including evolutionary hypothesis, studies on their GH/IGF-I axis and their immune system functioning. We illustrate in depth our recent studies on the ethnic group of Pygmies called Babinga, living in the forest of Cameroon, suggesting that the size of Pygmy subjects is reduced from birth, compared to a neighbouring population, and that it is associated with reduced GH and GH receptor gene expression. These results provide a research target for future epigenetic investigations and suggest that the short stature of African Pygmies is probably determined by complex genetic systems.