This review explains that puberty timing is heavily influenced by genetics. About 17 single‑gene mutations can delay or stop puberty, many of which also affect the sense of smell (Kallmann syndrome). A newer discovery shows the kisspeptin‑GPR54 pathway directly controls the brain cells that release the hormone GnRH, which starts puberty. Overall, genetics explain roughly 30% of puberty problems, and scientists are realizing that multiple genes often work together.

Puberty is controlled by genetic and environmental factors. This review examines the genetic basis for puberty by evaluating known gene mutations associated with disordered puberty in humans. At present, at least 17 different single-gene mutations are recognized as being associated with delayed or absent puberty in humans. Several of these genes are involved in the development of the olfactory nervous system, with mutations typically resulting in anosmia/hyposmia and hypogonadotropic hypogonadism, otherwise known as Kallmann syndrome. The biological basis for the association between smell and fertility is strong as development of the gonadotropin-releasing hormone (GnRH) neurons, responsible for regulating fertility, is intricately associated with development of the olfactory system. Other gene mutations, including the recently discovered kisspeptin-GPR54 signalling system, affect puberty by directly or indirectly modulating the functioning of the GnRH neurons and pituitary gonadotrophs. Together, these single-gene mutations are presently estimated to account for approximately 30% of individuals with disorders of puberty. A large number of different genes are involved in the complex process of bringing about reproductive competency. In addition to the genetic mutations associated with precocious and delayed puberty, the oligogenic aetiology of these conditions is being increasingly appreciated.