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In a landmark study, researchers from the Medical Research Council (MRC) Epidemiology Unit at the University of Cambridge reported significant findings on the genetic factors influencing puberty timing in girls.

The study, involving approximately 800,000 women across Europe, North America, China, Japan, and Korea, identified more than 1,000 genetic variants that impact the age of a girl's first menstrual period. Of these variants, around 600 were newly discovered, marking a substantial advancement in understanding puberty onset.

Puberty typically occurs between ages 10 to 15, but trends show earlier onset in recent decades, raising concerns due to its association with increased risks of type 2 diabetes, cardiovascular diseases, and certain cancers. Conversely, delayed puberty has been linked to better long-term health outcomes and longevity.

"Many of the genes we've found influence early puberty by first accelerating weight gain in infants and young children. This can then lead to potentially serious health problems in later life, as having earlier puberty leads to higher rates of overweight and obesity in adulthood," lead author Professor John Perry explained.

Previous research by the team, in collaboration with Cambridge's MRC Metabolic Diseases Unit, underscored the role of the MC3R brain receptor in regulating puberty timing based on nutritional signals. Additionally, other identified genes were found to affect the release of reproductive hormones in the brain.

The study published in Nature Genetics also analyzed rare genetic variants with significant impacts on puberty timing. For instance, variants in the ZNF483 gene were associated with a delay in puberty onset by an average of 1.3 years among carriers.

Dr. Katherine Kentistou, lead investigator, emphasized the study's scale in analyzing rare genetic variants, noting, "This is the first time we've ever been able to analyse rare genetic variants at this scale. We have identified six genes which all profoundly affect the timing of puberty. While these genes were discovered in girls, they often have the same impact on the timing of puberty in boys. The new mechanisms we describe could form the basis of interventions for individuals at risk of early puberty and obesity."

Using the data, researchers developed a genetic score predicting the likelihood of extremely early or late puberty onset. Girls with the highest 1% of this score were 11 times more likely to experience extremely delayed puberty (after age 15), while those with the lowest 1% were 14 times more likely to undergo extremely early puberty (before age 10), ScienceDaily reported.

Senior author Professor Ken Ong highlighted potential clinical applications, saying, "In the future, we may be able to use these genetic scores in the clinic to identify those girls whose puberty will come very early or very late. The NHS is already trialling whole genome sequencing at birth, and this would give us the genetic information we need to make this possible."