Legal Medicine

The development of a post-mortem interval estimation for human remains found on land in the Netherlands, yet some facts need further exploration

Non-pathological complete paternal uniparental isodisomy of chromosome 2 revealed in a maternity testing case Abstract We present a duo paternity test case to assess the biological relationship between a woman and her female child. After analyzing 57 autosomal and 19 X-chromosomal short tandem repeat loci, mother–daughter exclusions were discovered at four loci, which were all located on chromosome 2. Further testing of whole-genome single nucleotide polymorphisms confirmed that the daughter had complete uniparental disomy (UPD) of chromosome 2. This study presents a cautionary case demonstrating that hasty decisions of parentage exclusion should not be made when genetic markers on the same chromosome do not conform to Mendel’s laws due to UPD.

Self-inflicted long bone fractures for insurance fraud Abstract Self-inflicted fractures simulating traffic accident represent a new social fraud opportunity for criminality. Recognising scams through an increase of awareness of existence of self-inflicted arm fractures for insurance fraud could help community health workers to report these injuries to the competent authorities. In this article, authors have recognised an unusual but consistent pattern of upper and lower limb fractures whose incidence does not coincide in numerical terms with what is reported in literature. The aim of the present study is to describe fracture patterns observed over the past 2 years. Further, authors describe clinical presentations of these fractures and attempt to define a possible mechanism of these types of injuries.

Genetic analysis of 29 Y-STR loci in Han population from Dongfang, Southern China Abstract In the present study, blood samples of 984 unrelated Han individuals were collected from Dongfang, Southern China, after informed consent. A total of 29 Y-chromosomal short tandem repeat (Y-STR) were analyzed, including DYF387S1, DYS19, DYS385ab, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS437, DYS438, DYS439, DYS444, DYS447, DYS448, DYS449, DYS456, DYS458, DYS460, DYS481, DYS508, DYS518, DYS533, DYS576, DYS635, DYS643 and GATAH4. A total of 749 different haplotypes were found among 984 individuals, of which 645 were unique. The haplotype diversity was 0.9988 and the discrimination capacity was 0.7612, while the match probability was 0.0025. The smallest genetic distance (RST = 0.0155) was found between the Dongfang Han population and Guizhou Han population, while the largest genetic distance (RST = 0.1284) was observed with Gansu Tibetan.

Population genetic analysis of 30 insertion–deletion (INDEL) loci in a Qinghai Tibetan group using the Investigator DIPplex Kit Abstract The Qiagen Investigator® DIPplex Kit multiplexes 30 autosomal INDELs plus amelogenin for forensic use. The aim of this study was to estimate the diversity of 30 INDEL loci in a sample of 530 Tibetan individuals from Qinghai Province, China, and to evaluate the usefulness of these loci for forensic genetics. The observed heterozygosity ranged from 14.3 to 53.4%, and combined power of discrimination, matching probability, and cumulative probability of exclusion were 0.99999999999172, 8.27999 × 10−12, and 0.9897, respectively, in the Qinghai Tibetan group. The results of pairwise genetic distance, principal component analysis, a multi-dimensional scaling plot, and a neighbour-joining tree between the Qinghai Tibetan and 49 reference populations revealed significant genetic differences between continental populations and a close genetic relationship between the Qinghai Tibetan and East Asian populations. This study indicates that the Investigator® DIPplex Kit can serve as an effective supplementary tool for forensic genetic tasks.

Identification of tetragametic human chimerism by routine DNA profiling Abstract Chimerism in humans is defined as the presence of two genetically different cell lines within the same organism. It is usually an acquired condition that is restricted to certain tissues and can be explained by therapeutic interventions such as blood transfusion or the transplantation of allogenic hematopoietic cells. Implications of such patients for forensic DNA testing have been described in the literature. In some rare cases, true inherited chimerism is observed. This so called tetragametic chimerism occurs via the fertilization of the two ova by two spermatozoa, followed by the fusion of early embryos and the development of an organism with intermingled cell lines. Such examples have been found in mice and other mammalian species including humans. We describe a phenotypically normal woman in whom tetragametic chimerism (46,XX/46,XX) was unexpectedly identified by STR typing during routine DNA profiling. Cytogenetic analysis proved to be a valuable tool for both independent confirmation and direct visualization of the two coexisting cell lines.

Genetic variation among the major Pakistani populations based on 15 autosomal STR markers Abstract Pakistan is located at an important cross-road of human history and has been a passageway for many invaders and dynasties in the past. The historic human migrations across this country have resulted in a blend of ancient civilizations, which are still reflected in the current socio-cultural fabrication of this population. This makes Pakistan an ideal country to study the genetic differentiation and various other genomic aspects of a human population.

Microdeletion at 8q24.13 rather than multistep microsatellite mutation resulting in the genetic inconsistency at the D8S1179 locus in a true trio Abstract When using microsatellite loci for DNA paternity testing, genetic inconsistencies sometimes occur in true trios and duos and may be erroneously attributed to germline mutations of microsatellite alleles. Here, we reported a typical case and discussed the issue of how to find out the cause of a genetic inconsistency. In our case, a genetic inconsistency in a true trio was observed at the D8S1179 locus, where the father has only allele 10 as compared to only allele 16 of his son. A set of tests were then performed. The results showed that the inconsistency was not result from the germline mutation of allele 10 to allele 16, or from the presence of null alleles due to primer binding site mutations, but from the microdeletion at 8q24.13, about 2.99 to 49.76 kb, detected in both the father and his son, which revealed by deletion mapping using short tandem repeats (STRs) and single nucleotide polymorphisms (SNPs). In conclusion, genetic inconsistencies observed in true trios or duos cannot be rashly attributed to germline STR mutations, especially multistep mutations, in the absence of verification or specification; otherwise, the reliability of the genetic proofs established will be challenged.

Phase I metabolic profiling of the synthetic cannabinoids THJ-018 and THJ-2201 in human urine in comparison to human liver microsome and cytochrome P450 isoenzyme incubation Abstract Despite the increasing relevance of synthetic cannabinoids as one of the most important classes within “New Psychoactive Substances”, there is still a lack of knowledge concerning their metabolism in humans. Due to the extensive metabolism of synthetic cannabinoids, metabolites are necessarily the best target analytes in urine, posing additional challenges to forensic analysis. The aims of this study were to identify appropriate urinary targets indicating intake of THJ-018 or THJ-2201 as well as to elucidate the most important cytochrome P450 isoenzymes within the metabolism of THJ-018 and THJ-2201 in vitro. For this purpose, the in vitro metabolism of THJ-018 and THJ-2201 was initially established using pooled human liver microsomes. The results obtained were compared to previously published in vitro results as well as to the results of the metabolic profiles from selected recombinant cytochrome P450 isoenzymes and from 23 urine samples from forensic cases. LC-HRMS was used to conduct product ion scans and to examine the metabolite spectra. For THJ-018, 17 different metabolite groups containing 33 different metabolites and isomers were detected after microsomal incubation, with the major metabolic pathways being monohydroxylation at the pentyl chain and of the naphthyl moiety as well as dihydroxylation of both residues. For THJ-2201, 19 different metabolite groups and 46 different metabolites and isomers were observed. The major metabolic pathways were monohydroxylation at the naphthyl moiety and oxidative defluorination. Significant contribution to the in vitro metabolism of THJ-018 and THJ-2201 originated from CYP2B6, CYP2C19, CYP3A4, and CYP3A5. As several cytochrome P450 isoenzymes are involved in the metabolism of these synthetic cannabinoids, a co-consumption with other drugs is unlikely to have an impact on their metabolism.

Technical note: developmental validation of a novel 6-dye typing system with 36 Y-STR loci Abstract Y-chromosomal short tandem repeats (Y-STRs) have proven to be very useful in investigating sexual assault cases and in paternity lineage differentiation. However, currently available commercial Y-STR multiplex amplification systems bear the limitations in the identification of related males from the same paternal lineage due to there being an insufficient number of loci in any single amplification kit. The aim of this study was to establish and validate a novel 6-dye, 36-plex Y-STR multiplex amplification system that incorporated all of the loci present in the Yfiler™ Plus kit (DYS19, DYS385a/b, DYF387S1, DYS389I/II, DYS390, DYS391, DYS392, DYS393, DYS437, DYS438, DYS439, DYS448, DYS449, DYS456, DYS458, DYS460, DYS481, DYS518, DYS533, DYS570, DYS576, DYS627, DYS635, Y_GATA_H4) as well as a further nine highly polymorphic Y-STR loci (DYS388, DYS444, DYS447, DYS522, DYS527a/b, DYS549, DYS596, DYS643). The novel system was optimized and validated by a series of studies that tested the effect of different PCR-based conditions as well as the species specificity, sensitivity, stability, stutter precision, suitability for use on DNA mixtures, reproducibility, and parallel testing of the system, as well as its performance on casework samples and population analysis, according to the SWGDAM developmental validation guidelines. A total of 246 haplotypes were found for the 36 Y-STRs among 247 Guangdong Han unrelated males. Collectively, the results demonstrate that the developed 36-plex Y-STR system is sensitive, robust, reliable, and highly informative for use in forensic genetics.