Minors arriving at European borders are entitled to special legal protections to ensure they are treated fairly. However, many unaccompanied minors are unable to prove that they are underage and are therefore subjected to a range of medical and non-medical procedures, many of which are highly invasive. Such procedures vary between countries but include physical examinations and X-ray analysis. For this reason, efforts are being made to identify less invasive procedures that could replace the current ones. In recent years several studies have investigated DNA methylation as a potential alternative method to predict legal age.

In this study, we further explore the viability of DNA methylation for such use. To this end, we selected three published epigenetic clocks trained in blood to evaluate the differences and limitations associated with each when estimating the age of young individuals. These models were selected because, although they predict age in blood, they differ in several aspects, as the number or biomarkers included and the age range of the training data. When evaluated across several cohorts of samples, the models displayed differing tendencies in age prediction. Although the overall prediction errors were low, some of these tendencies showed to be prejudicial towards minors in the context of legal age estimation.

Based on the results obtained, we aimed to develop different strategies to overcome the limitations identified for each of the tested models. The final objective was to identify and, where possible, mitigate the drawbacks of using DNA methylation for legal age assessment thereby improving its potential as a viable alternative to current procedures.

The study received funding from the European Union’s Horizon Europe Programme under Grant agreement no. 101225631. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or REA.

Authors

• Miguel Boullón-Cassau (Forensic Genetics Unit, Institute of Forensic Sciences, Universidade de Santiago de Compostela, Spain)
• Mafalda Silva (Forensic Genetics Unit, Institute of Forensic Sciences, Universidade de Santiago de Compostela, Spain)
• Aleksandra Pisarek-Pacek (Institute of Zoology and Biomedical Research, Jagiellonian University, Poland)
• María de los Ángeles Casares de Cal (CITMAga (Center for Mathematical Research and Technology of Galicia), Universidade de Santiago de Compostela, Spain)
• Antonio Gómez-Tato (CITMAga (Center for Mathematical Research and Technology of Galicia), Universidade de Santiago de Compostela, Spain)
• Adrián Ambroa-Conde (Forensic Genetics Unit, Institute of Forensic Sciences, Universidade de Santiago de Compostela, Spain)
• Ewelina Pośpiech (Department of Genomics and Forensic Genetics, Pomeranian Medical University, Poland)
• Kamila Marszałek (Department of Genomics and Forensic Genetics, Pomeranian Medical University, Poland)
• Walther Parson (Institute of Legal Medicine, Medizinische Universität Innsbruck, Austria; Forensic Science Program, The Pennsylvania State University, University Park, PA, United States of America)
• Antonia Heidegger (Institute of Legal Medicine, Medizinische Universität Innsbruck, Austria)
• M Victoria Lareu (Forensic Genetics Unit, Institute of Forensic Sciences, Universidade de Santiago de Compostela, Spain)
• Wojciech Branicki (Institute of Zoology and Biomedical Research, Jagiellonian University; Institute of Forensic Research in Kraków, Poland)
• Ana Freire-Aradas (Forensic Genetics Unit, Institute of Forensic Sciences, Universidade de Santiago de Compostela, Spain)