Medico-legal aspects of sexual violence – Forensic Genetics makes a difference.

Background and aims: Medico-legal examination plays a key role in handling sexual assault victims and medical care must be combined with a validated evidences collection procedure to ensure the appropriate chain of custody in order to assist the criminal investigation process. The aim of this study was to evaluate the success rates of DNA analysis of biological traces collected upon the examination of women victims of sexual violence following the recommendations of the Italian Forensic Geneticists. (Ge.F.I.). Materials and methods: This retrospective study was conducted on thirty-six selected caseworks of alleged sexual assault analyzed in the laboratory of Forensic Genetics of the University of Bologna, on the request of the Prosecutor Office, in the years 2007-2014. All victims were adult female, but data of time elapsed from the assault to the examination were not always available. The collection of biological samples for the DNA analysis was performed in the Hospital Emergency Department following an internal procedure based on the recommendations of the Italian Forensic Geneticists. (Ge.F.I.). For each 36 caseworks, different kind of evidences were analyzed: vaginal, cervical, rectal and oral swabs, fingernail scraping, histological slides set up from vaginal swabs and other samples collected at crime scene (clothes, underwear, blankets, shoes, glasses and condoms). The reference sample of the person under investigation was available for comparisons in 19 caseworks. Results: The autosomal DNA profile was obtained from clothes, underwear and blankets in 22 caseworks (70%). Haplotype of the human Y chromosome was informative in 18 caseworks (82%). DNA degradation was never experienced. DNA profile matching the suspect was obtained in 63% of cases. Conclusions: The high percentage of genetic profile obtained (70%) from the collected biological evidences, the absence of degradation and contamination events of DNA profiles, the match with the suspect in 63% of cases confirm that DNA analysis of biological evidences collected according to recommendations and guidelines of Ge.F.I. makes a difference in the medico-legal care for victims of sexual violence.