Case report: on the use of the HID-Ion AmpliSeq™ Ancestry Panel in a real forensic case.

In the absence of any other conclusive forensic evidence, DNA profiling is the method of choice for body identification. This study focuses on the case of a carbonized corpse whose complete autosomal short tandem repeat (STR) profile could not lead to direct identification by the investigators. To assist in the progress of investigation, we endeavoured to determine the biogeographical origin and eye colour of the deceased individual. Along with Y chromosome and mitochondrial DNA analyses, we applied a next-generation sequencing (NGS) approach to the study of ancestry informative markers (AIMs) using the HID-Ion AmpliSeq™ Ancestry Panel launched by Thermo Fisher Scientific. This work gave us the opportunity to test this new technology in a real forensic case. Although this study highlights the benefits of such a combined approach, as it markedly improves the specificity of the biogeographical profile, it also underlines the need for the accurate characterization of a larger collection of reference populations and the necessity of caution in data interpretation.

Targeted next generation sequencing application in cardiac channelopathies: Analysis of a cohort of autopsy-negative sudden unexplained deaths.

Genetic testing for cardiac channelopathies in sudden unexplained death (SUD) has developed substantially over the last years. The Next Generation Sequencing (NGS) technology provides an unprecedented opportunity to screen for genetic variations underlying arrhythmogenic genes in a short period of time at a low cost. The present study aimed to perform genetic testing with NGS technologies on the Ion Torrent Personal Genome Machine™ (Ion PGM™) sequencer, in targeting a total of 23 genes reported to be associated with inherited cardiac channelopathies in order to identify the possible cause of death in a cohort of post-mortem cases. The molecular analyses focused on 16 cases of SUD, aged less than 35 years old. In all cases, the cause of death could not be determined after a rigorous autopsy associated with histopathological and toxicological analyses according to the guidelines of the Association for European Cardiovascular Pathology. DNA was extracted from fresh frozen tissue. An average of 200 variants was identified per case. However, after the prioritization process using a new scoring program (VaRank) and after the conjunction of clinical data and molecular findings, four "likely pathogenic" variants (including two undescribed variants), were identified in three cases (18.75%) of our cohort in the genes KCNH2, ANK2, SCN5A and RYR2. One case, who died during psychiatric hospitalization after administration of a QT prolonging drug, showed a double "likely pathogenic" variant in Long QT genes (ANK2 and SCN5A) which may have predisposed to drug-induced cardiac arrhythmias. Our study illustrates that the NGS approach based on AmpliSeq™ libraries and Ion Torrent PGM™ sequencing may be an efficient approach, integrated to post-mortem examination. Given the massive amount of information generated by NGS, a rigorous filtration strategy of variants coupled with multidisciplinary collaboration is crucial to determine the potential pathogenic role of identified variants in the cause of death.

RNA/DNA co-analysis from human skin and contact traces--results of a sixth collaborative EDNAP exercise.

The European DNA profiling group (EDNAP) organized a sixth collaborative exercise on RNA/DNA co-analysis for body fluid/tissue identification and STR profiling. The task was to identify skin samples/contact traces using specific RNA biomarkers and test three housekeeping genes for their suitability as reference genes. Eight stains, a skin RNA dilution series and, optionally, bona fide or mock casework samples of human or non-human origin were analyzed by 22 participating laboratories using RNA extraction or RNA/DNA co-extraction methods. Two sets of previously described skin-specific markers were used: skin1 pentaplex (LCE1C, LCE1D, LCE2D, IL1F7 and CCL27) and skin2 triplex (LOR, KRT9 and CDSN) in conjunction with a housekeeping gene, HKG, triplex (B2M, UBC and UCE). The laboratories used different chemistries and instrumentation. All laboratories were able to successfully isolate and detect mRNA in contact traces (e.g., human skin, palm-, hand- and fingerprints, clothing, car interiors, computer accessories and electronic devices). The simultaneous extraction of RNA and DNA provides an opportunity for positive identification of the tissue source of origin by mRNA profiling as well as a simultaneous identification of the body fluid donor by STR profiling. The skin markers LCE1C and LOR and the housekeeping gene marker B2M were detected in the majority of contact traces. Detection of the other markers was inconsistent, possibly due to the low amounts and/or poor quality of the genetic material present in shed skin cells. The results of this and the previous collaborative RNA exercises support RNA profiling as a reliable body fluid/tissue identification method that can easily be combined with current STR typing technology.

RNA/DNA co-analysis from human menstrual blood and vaginal secretion stains: results of a fourth and fifth collaborative EDNAP exercise.

The European DNA Profiling Group (EDNAP) organized a fourth and fifth collaborative exercise on RNA/DNA co-analysis for body fluid identification and STR profiling. The task was to identify dried menstrual blood and vaginal secretion stains using specific RNA biomarkers, and additionally test 3 housekeeping genes for their suitability as reference genes. Six menstrual blood and six vaginal secretion stains, two dilution series (1/4-1/64 pieces of a menstrual blood/vaginal swab) and, optionally, bona fide or mock casework samples of human or non-human origin were analyzed by 24 participating laboratories, using RNA extraction or RNA/DNA co-extraction methods. Two novel menstrual blood mRNA multiplexes were used: MMP triplex (MMP7, MMP10, MMP11) and MB triplex (MSX1, LEFTY2, SFRP4) in conjunction with a housekeeping gene triplex (B2M, UBC, UCE). Two novel mRNA multiplexes and a HBD1 singleplex were used for the identification of vaginal secretion: Vag triplex (MYOZ1, CYP2B7P1 and MUC4) and a Lactobacillus-specific Lacto triplex (Ljen, Lcris, Lgas). The laboratories used different chemistries and instrumentation and all were able to successfully isolate and detect mRNA in dried stains. The simultaneous extraction of RNA and DNA allowed for positive identification of the tissue/fluid source of origin by mRNA profiling as well as a simultaneous identification of the body fluid donor by STR profiling, also from old and compromised casework samples. The results of this and the previous collaborative RNA exercises support RNA profiling as a reliable body fluid identification method that can easily be combined with current STR typing technology.

RNA/DNA co-analysis from human saliva and semen stains--results of a third collaborative EDNAP exercise.

A third collaborative exercise on RNA/DNA co-analysis for body fluid identification and STR profiling was organized by the European DNA Profiling Group (EDNAP). Twenty saliva and semen stains, four dilution series (10-0.01 µl saliva, 5-0.01 µl semen) and, optionally, bona fide or mock casework samples of human or non-human origin were analyzed by 20 participating laboratories using an RNA extraction or RNA/DNA co-extraction method. Two novel mRNA multiplexes were used: a saliva triplex (HTN3, STATH and MUC7) and a semen pentaplex (PRM1, PRM2, PSA, SEMG1 and TGM4). The laboratories used different chemistries and instrumentation and a majority (16/20) were able to successfully isolate and detect mRNA in dried stains. The simultaneous extraction of RNA and DNA from individual stains not only permitted a confirmation of the presence of saliva/semen (i.e. tissue/fluid source of origin), but allowed an STR profile of the stain donor to be obtained as well. The method proved to be reproducible and sensitive, with as little as 0.05 µl saliva or semen, using different analysis strategies. Additionally, we demonstrated the ability to positively identify the presence of saliva and semen, as well as obtain high quality DNA profiles, from old and compromised casework samples. The results of this collaborative exercise involving an RNA/DNA co-extraction strategy support the potential use of an mRNA based system for the identification of saliva and semen in forensic casework that is compatible with current DNA analysis methodologies.