Review of the Literature on Current Changes in the Timing of Pubertal Development and the Incomplete Forms of Early Puberty

Abstract

Puberty is a sensitive period of life characterized by the appearance of secondary sex characteristics which leads to a complete sexual maturation. It physiologically starts between the age of 8 and 13 years in girls and 9 and 14 years in boys. In the last two decades, several studies have showed that start of puberty has moved up to younger ages by 12–18 months, and some of the hypotheses trying to explain this change include the role of nutritional status and obesity and the influence of extrinsic factors such as exposure to endocrine-disrupting chemicals (EDCs), as well. The hypothalamic–hypophysis–gonadal axis develops during embryogenesis, and except for a period of activation immediately after birth, remains suppressed until the onset of pubertal development. At the beginning of puberty, the pulse generator is reactivated, probably due to progressive stimulatory influences on GnRH neurons from glial signals and neurotrasmitters. Kisspeptin and its receptor play a fundamental role in this phase. Premature Pubarche/Adrenarche, Premature Thelarche, and Premature Menarche are incomplete forms of precocious pubertal development that have their origin in endocrine mechanisms that only recently have started to be understood. It is important to distinguish these forms from the complete ones in order to reassure patients and parents about the non-evolution of pubertal progression and avoid non-useful treatments with analogous LHRH.

“Age Related Differences in the Biology of Chronic Graft-Versus-Host Disease After Hematopoietic Stem Cell Transplantation”

“…Puberty is the result of activation of the hypothalamopituitary-gonadal axis and, as a consequence, of the increased production of androgens and estrogens usually starting between the age of 8 and 13 years in girls and 9 and 14 years in boys (9). Onset of puberty is associated with a decline in thymic function, and possibly splenic function as well (10,11). Yet, the exact differences that age and puberty have on the development of immune reconstitution post-HSCT, GvHD, and the induction of immune tolerance are still incompletely studied.…”

Factors affecting bone maturation in Chinese girls aged 4-8 years with isolated premature thelarche

“…IPT presented in an elder age is also considered to be a benign and selflimiting phenomenon that usually not in uence the growth or timing of puberty. Generally, bone age (BA) in IPT girls is consistent with chronological age (CA) [2][3][4].…”

Factors affecting bone maturation in 423 Chinese girls aged 4-8 years with isolated premature thelarche

“…It is a benign and self-limiting phenomenon that usually does not influence the growth or timing of puberty. Generally, bone age (BA) in IPT girls is consistent with chronological age (CA) [2][3][4].…”