Within a period of only 15 years, Danish girls’ pubertal onset has decreased from 11 to 10 years. Similar, but less pronounced, changes have been observed in boys. This has led researchers to question the involvement of genetics and recognize that genes are not alone in influencing a child’s pubertal timing.
In this new study, researchers therefore focused on the role of epigenetics and have found a number of areas in the human genome, which is controlled epigenetically during puberty. The researchers found that these epigenetic changes cause the upregulation of genes that are important for pubertal development. One of the newly discovered 'puberty genes' is TRIP6 (Thyroid Hormone Receptor Interactor 6), which is increasingly expressed through puberty, due to changes in the epigenetic control of the gene.
Epigenetics is a leading mechanism by which our environment communicates with our genes. Environmental and lifestyle factors in the broadest sense can affect the epigenetic regulation of genes and thereby control whether, where and to what extent the genes are expressed. The identified epigenetic changes during puberty are therefore our best lead towards understanding how environmental factors can affect pubertal onset.
"To our knowledge, this study is the first to demonstrate how the environment can affect the pubertal onset in humans. It gives us a significant insight in to the crucial role of epigenetic factors on our reproductive development," says Professor Anders Juul, Senior author of the study. He continues:
“We’ve seen a tendency of especially girls starting puberty earlier than before and this study emphasizes the importance of understanding the role of environmental impact on pubertal development.”
Highly specific changes in methylation of a child’s DNA could differentiate children according to whether they had entered puberty or not and thus may be used to predict a child’s pubertal stage.
"Changes in the DNA methylation patterns can be caused by many different factors. However, we could see very specific changes when children went through puberty, and have subsequently shown that this also leads to changes in the expression of the methylated genes,” comments Senior Researcher in epigenetics Kristian Almstrup, who led the study.
About the study
Blood samples from boys and girls, taken before and during puberty, have been examined for changes in DNA methylation patterns (an expression of the epigenetic control). The children were part of the large COPENHAGEN Puberty Study from EDMaRC and the Department of Growth and Reproduction at Rigshospitalet.
The study has been published in the scientific journal; Scientific Reports and can be found here
EDMaRC is the international center for research and research training in Endocrine Disruption of Male Reproduction and Child Health. EDMaRC is located at the Department of Growth and Reproduction at Rigshospitalet and has close collaboration with the University of Copenhagen. Professor Anders Juul is Head of Management and Professor Jorma Toppari from University of Turku serves as Chair of the Scientific Steering Group. For more information about EDMaRC please visit the website: www.edmarc.net For further information please contact Dina Muscat Meng, EDMaRC Project Coordinator on phone: +45 45 3545 1865 or email: firstname.lastname@example.org