AUTHOR=Bianco Suzy 

TITLE=A potential mechanism for the sexual dimorphism in the onset of puberty and incidence of idiopathic central precocious puberty in children: sex-specific kisspeptin as an integrator of puberty signals

JOURNAL=Frontiers in Endocrinology

VOLUME=Volume 3 - 2012

YEAR=2012

URL=https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2012.00149

DOI=10.3389/fendo.2012.00149

ISSN=1664-2392

ABSTRACT=The major determinants of the variability in pubertal maturation are reported to be genetic and inherited. Nonetheless, nutritional status contributes significantly to this variability. Malnutrition delays puberty whereas obesity has been associated to a rise in Idiopathic Central Precocious Puberty (ICPP) in girls. However, epidemiology data indicate that contribution of obesity to early puberty varies significantly among ethnic groups, and that obesity-independent inheritable genetic factors are the strongest predictors of early puberty in any ethnic group. In fact, the two human mutations with confirmed association to ICPP reported to date were identified in children with no history of obesity. These mutations are in kisspeptin and kisspeptin receptor, a ligand/ receptor pair with a major role on the onset of puberty and female cyclicity after puberty. Hypothalamic expression of kisspeptin is reported to be sexually dimorphic in many species, which include humans. The hypothalamus of females is programmed to express significantly higher levels of kisspeptin than their male counterparts; and progressive increases in kisspeptin expression in hypothalamic nuclei known to regulate reproductive function have been associated to the onset of puberty. Interestingly, the incidence of ICPP and delayed puberty in children is markedly sexually dimorphic, such that ICPP is at least 10-fold more frequent in girls, whereas prevalence of delayed puberty is about 5-fold higher in boys. These observations are consistent with a possible involvement of sexually dimorphic kisspeptin signaling in the sexual dimorphism of pubertal disorders in children of all ethnicities. This review discusses the likelihood of such associations, as well as a potential role of kisspeptin as the converging target of environmental, metabolic and hormonal signals that are integrated in order to optimize reproductive function.