Genes have been identified to play a role in influencing the onset of puberty in girls, either indirectly through accelerating childhood weight gain or directly impacting the age at which puberty occurs. Researchers at the University of Cambridge led an international study involving approximately 800,000 women from various regions, revealing over 1,000 genetic variants that influence the age of a girl’s first menstrual period, with around 600 variants being newly discovered.
The average age range for puberty onset is between 10 to 15 years, though this has been decreasing over recent decades. Early puberty is associated with an increased risk of several diseases later in life, such as type 2 diabetes, heart disease, and certain cancers. Conversely, later puberty has been linked to better health outcomes in adulthood and a longer lifespan.
Nearly half of the identified genetic variants were found to impact puberty indirectly by promoting weight gain in early childhood. This weight gain can lead to health issues in adulthood, as early puberty is associated with higher rates of obesity.
One notable gene discovered, MC3R, located in the brain, appears to play a significant role in regulating puberty timing and growth in children by detecting the body’s nutritional status. Other genes influence the release of reproductive hormones in the brain.
The study also analyzed rare genetic variants that, despite being carried by a small number of individuals, can have a significant impact on puberty timing. For instance, variants in the ZNF483 gene were found to delay puberty by an average of 1.3 years in 1 out of 3,800 women.
The researchers developed a genetic score that could predict the likelihood of a girl experiencing very early or very late puberty. Girls with the highest 1% of this score were 11 times more likely to have extremely delayed puberty past 15 years of age, while those with the lowest score were 14 times more likely to have extremely early puberty before the age of 10.
Moving forward, these genetic scores could potentially be used in clinical settings to identify girls at risk of early or delayed puberty. This information could guide interventions to manage puberty timing and associated health implications. The study was supported by the Medical Research Council and utilized data from the UK Biobank.
