Reproductive function in women is closely linked to factors such as nutrition, neuroendocrine signals and genetics. It is known that gene-environment interaction can influence the premature onset of menarche.
Menarche is the name given to the first menstruation in women. It typically occurs about two years after the appearance of pubic hair and incipient breasts, and can occur prematurely before the age of 8 or delayed until the age of 16.
The first menstruation symbolizes a state of maturity characterized by the preparation of the young woman's body for reproduction and greater clarity as to sexual identity.
Menstruation or period is the normal vaginal bleeding that occurs as part of a woman's monthly cycle. Every month, her body prepares for a possible pregnancy. If this does not occur, the uterus sheds its lining (endometrium), which is shed with menstrual bleeding, and is renewed in the next cycle.
Daughters of mothers with an early age of menarche are more likely to have an early onset of menarche.
The onset of menarche is influenced by different environmental factors such as physical activity, diet or birth weight, as well as genetic factors affecting the development of this trait.
An early age at menarche has been associated with a certain predisposition to obesity, metabolic syndrome and shorter stature, among other effects.
It is estimated that the heritability of early menarche ranges from 57 to 82%. Related genes have been described such as: LIN28B, DLK1, MKRN3 and KCNK9.
One of the most recent genome-wide association studies, involving about 200,000 people of European ancestry, has identified 172 markers related to the onset of menstruation. Notable among the associated genes in this study is LIN28B, which had already been linked to this trait in other genome-wide association studies. In addition to being linked to early onset of puberty, it has also been found to be associated with shorter stature.
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