Age determination through DNA methylation patterns in fingernails and toenails. (May 2023)

• Record Type: Journal Article
• Authors: Fokias, Kristina; Dierckx, Lotte; Van de Voorde, Wim; Bekaert, Bram
• Is Part Of: Forensic science international. Volume 64(2023)
• Publication Date: 2023-05
• Subjects: Forensic -- DNA methylation -- Age determination; Forensic genetics -- Periodicals; Génétique légale -- Périodiques; Forensic genetics; Electronic journals; Periodicals; 614.1
• DOI: 10.1016/j.fsigen.2023.102846
• Languages: English
• ISSNs: 1872-4973

Abstract

Abstract: Over the past decade, age prediction based on DNA methylation has become a vastly investigated topic; many age prediction models have been developed based on different DNAm markers and using various tissues. However, the potential of using nails to this end has not yet been explored. Their inherent resistance to decay and ease of sampling would offer an advantage in cases where post-mortem degradation poses challenges concerning sample collection and DNA-extraction. In the current study, clippings from both fingernails and toenails were collected from 108 living test subjects (age range: 0–96 years). The methylation status of 15 CpGs located in 4 previously established age-related markers (ASPA, EDARADD, PDE4C, ELOVL2) was investigated through pyrosequencing of bisulphite converted DNA. Significant dissimilarities in methylation levels were observed between all four limbs, hence both limb-specific age prediction models and prediction models combining multiple sampling locations were developed. When applied to their respective test sets, these models yielded a mean absolute deviation between predicted and chronological age ranging from 5.48 to 9.36 years when using ordinary least squares regression. In addition, the assay was tested on methylation data derived from 5 nail samples collected from deceased individuals, demonstrating its feasibility for application in post-mortem cases. In conclusion, this study provides the first proof that chronological age can be assessed through DNA methylation patterns in nails. Highlights: DNA from finger- and toenails was extracted for forensic age prediction modelling. The DNA methylation status of 15 CpGs located in 4 age-related markers was evaluated. DNA methylation data from finger- and toenails was assessed separately and combined. The age prediction models yielded mean absolute deviations of 5.48 to 9.36 years. Preliminary data indicates the potential use of the assay in post-mortem cases. This study is the first to demonstrate age prediction modelling using DNA from nails.