A Ge.F.I. - ISFG European collaborative study on DNA identification of Cannabis sativa samples using a 13-locus multiplex STR method.

Cannabis sativa is the most used controlled substance in Europe. With the advent of new and less restrictive European laws on cannabis sale for recreational use (including in Italy), an increase in indoor cannabis crops were observed. This increase was possible due to the availability of cannabis seeds through the internet market. Genetic identification of cannabis can link seizures and if in possession then might aid in an investigation. A 13-locus multiplex STR method was previously developed and validated by Houston et al. A collaborative exercise was organized by the Italian Forensic Geneticists - International Society of Forensic Genetics (Ge.F.I. - ISFG) Working Group with the aim to test the reproducibility, reliability and robustness of this multiplex cannabis STR kit. Twenty-one laboratories from three European countries participated in the collaborative exercise and were asked to perform STR typing of two cannabis samples. Cannabis DNA samples and the multiplex STR kit were provided by the University of Barcelona and Sam Houston State University. Different platforms for PCR amplification, capillary electrophoresis (CE) and genotyping software were selected at the discretion of the participating laboratories. Although the participating laboratories used different PCR equipment, CE platforms and genotyping software, concordant results were obtained from the majority of the samples. The overall genotyping success ratio was 96%. Only minor artifacts were observed. The mean peak height ratio was estimated to be 76.3% and 78.1% for sample 1 and sample 2, respectively. The lowest amount of -1 / + 1 stutter percentage produced, when the height of the parent allele was higher than 8000 RFU, resulted to be less than 10% of the parent allele height. Few common issues were observed such as a minor peak imbalance in some heterozygous loci, some artifact peaks and few instances of allelic drop-out. The results of this collaborative exercise demonstrated the robustness and applicability of the 13-locus system for cannabis DNA profiling for forensic purposes.

GHEP-ISFG collaborative exercise on mixture profiles (GHEP-MIX06). Reporting conclusions: Results and evaluation.

One of the main goals of the Spanish and Portuguese-Speaking Group of the International Society for Forensic Genetics (GHEP-ISFG) is to promote and contribute to the development and dissemination of scientific knowledge in the field of forensic genetics. Due to this fact, GHEP-ISFG holds different working commissions that are set up to develop activities in scientific aspects of general interest. One of them, the Mixture Commission of GHEP-ISFG, has organized annually, since 2009, a collaborative exercise on analysis and interpretation of autosomal short tandem repeat (STR) mixture profiles. Until now, six exercises have been organized. At the present edition (GHEP-MIX06), with 25 participant laboratories, the exercise main aim was to assess mixture profiles results by issuing a report, from the proposal of a complex mock case. One of the conclusions obtained from this exercise is the increasing tendency of participating laboratories to validate DNA mixture profiles analysis following international recommendations. However, the results have shown some differences among them regarding the edition and also the interpretation of mixture profiles. Besides, although the last revision of ISO/IEC 17025:2017 gives indications of how results should be reported, not all laboratories strictly follow their recommendations. Regarding the statistical aspect, all those laboratories that have performed statistical evaluation of the data have employed the likelihood ratio (LR) as a parameter to evaluate the statistical compatibility. However, LR values obtained show a wide range of variation. This fact could not be attributed to the software employed, since the vast majority of laboratories that performed LR calculation employed the same software (LRmixStudio). Thus, the final allelic composition of the edited mixture profile and the parameters employed in the software could explain this data dispersion. This highlights the need, for each laboratory, to define through internal validations its criteria for editing and interpreting mixtures, and to continuous train in software handling.

Development of an Italian RM Y-STR haplotype database: Results of the 2013 GEFI collaborative exercise.

Recently introduced rapidly mutating Y-chromosomal short tandem repeat (RM Y-STR) loci, displaying a multiple-fold higher mutation rate relative to any other Y-STRs, including those conventionally used in forensic casework, have been demonstrated to improve the resolution of male lineage differentiation and to allow male relative separation usually impossible with standard Y-STRs. However, large and geographically-detailed frequency haplotype databases are required to estimate the statistical weight of RM Y-STR haplotype matches if observed in forensic casework. With this in mind, the Italian Working Group (GEFI) of the International Society for Forensic Genetics launched a collaborative exercise aimed at generating an Italian quality controlled forensic RM Y-STR haplotype database. Overall 1509 male individuals from 13 regional populations covering northern, central and southern areas of the Italian peninsula plus Sicily were collected, including both "rural" and "urban" samples classified according to population density in the sampling area. A subset of individuals was additionally genotyped for Y-STR loci included in the Yfiler and PowerPlex Y23 (PPY23) systems (75% and 62%, respectively), allowing the comparison of RM and conventional Y-STRs. Considering the whole set of 13 RM Y-STRs, 1501 unique haplotypes were observed among the 1509 sampled Italian men with a haplotype diversity of 0.999996, largely superior to Yfiler and PPY23 with 0.999914 and 0.999950, respectively. AMOVA indicated that 99.996% of the haplotype variation was within populations, confirming that genetic-geographic structure is almost undetected by RM Y-STRs. Haplotype sharing among regional Italian populations was not observed at all with the complete set of 13 RM Y-STRs. Haplotype sharing within Italian populations was very rare (0.27% non-unique haplotypes), and lower in urban (0.22%) than rural (0.29%) areas. Additionally, 422 father-son pairs were investigated, and 20.1% of them could be discriminated by the whole set of 13 RM Y-STRs, which was very close to the theoretically expected estimate of 19.5% given the mutation rates of the markers used. Results obtained from a high-coverage Italian haplotype dataset confirm on the regional scale the exceptional ability of RM Y-STRs to resolve male lineages previously observed globally, and attest the unsurpassed value of RM Y-STRs for male-relative differentiation purposes.

The 2011 GeFI collaborative exercise. Concordance study, proficiency testing and Italian population data on the new ENFSI/EDNAP loci D1S1656, D2S441, D10S1248, D12S391, D22S1045.

The 2011 collaborative exercise of the ISFG Italian Working Group GeFI was aimed at validating the five ENFSI/EDNAP miniSTR loci D1S1656, D2S441, D10S1248, D12S391 and D22S1045. The protocol required to type at least 50 multilocus profiles from locally resident individuals and two blind bloodstains in duplicate (i.e., using at least two different commercial kits), and to send the electropherograms to the Organizing Committee. Nineteen laboratories distributed across Italy participated, collecting a total of 960 samples. Full concordance was found for the five new miniSTRs as observed from the comparison of 13,150 alleles. The inspection of the electropherograms allowed the identification of a very limited number of mistypings in the miniSTR genotypes thus contributing to the establishment of an high quality Italian database of frequencies.

Multiplex mtDNA coding region SNP assays for molecular dissection of haplogroups U/K and J/T.

Mitochondrial DNA (mtDNA) U/K and J/T are sister haplogroups within the superhaplogroup R. They are both common in Europe, with a combined overall frequency similar to the one reported for H, the most common European haplogroup (40-50%). In this study, we selected 159 Italian subjects, already ascribed to U/K and J/T by RFLP typing, and assigned each mtDNA to specific clades/subclades by investigating at least one diagnostic coding region SNP. For each sister haplogroup, one multiplex PCR and one SNaPshot minisequencing reaction were set up targeting 16 U/K and 7 J/T coding region SNPs. Each mtDNA sample was clearly assigned to a specific subclade, which could be further subdivided into several minor sub-branches according to peculiar HVS I/II motifs. Such a molecular dissection of haplogroups U/K and J/T could be extremely useful to reduce the overall analysis time and labor intensive sequencing procedures in high volume forensic casework, for example when it is important to rapidly exclude samples in order to restrict the number of suspects.

Cardiovascular involvement in thalassaemic patients with pseudoxanthoma elasticum-like skin lesions: a long-term follow-up study.

BACKGROUND: Congenital haemolytic anaemia may be associated with pseudoxanthoma elasticum (PXE)-like clinical manifestations. METHODS: The cardiovascular system of 14 homozygous and double heterozygous beta-thalassaemia patients with skin and retinal vessel alterations similar to those in genetic PXE was analysed over a period of 12 years and compared with that of 13 relatives (five sets of parents, one single parent, two thalassaemic brothers), and that of the control group composed of 16, age- and sex-matched, thalassaemic patients. RESULTS: All patients with clinical PXE-like skin lesions exhibited, by light and electron microscopy, dermal alterations and mineralization of elastic fibres identical to those typical of inherited PXE. None of the relatives and none of the control group showed clinical or structural findings of PXE. The follow-up started in 1988. After 12 years of clinical observation, six patients showed dramatic progression of skin involvement, angioid streaks had progressed in two subjects. One patient had recurrent gastrointestinal bleeding and underwent partial stomach removal for gastric artery aneurysm, one underwent colon resection for intestinal infarct, one patient had a transitory ischaemic attack, one died after an intracranial haemorrhage, two patients died from cardiovascular disease and one from neoplasia. CONCLUSIONS: Thalassaemic patients with PXE-like skin lesions also manifest PXE-like vessel alterations that progress with time. Considering the severe outcome of these lesions, accurate monitoring should be routinely performed on the cardiovascular system of thalassaemic patients with PXE-like skin manifestations.

Y-chromosome haplotypes in Italy: the GEFI collaborative database.

A sample of 1176 males from 10 Italian regions have been typed for DYS19, DYS389-I, DYS389-II, DYS390, DYS391, DYS392, DYS393, and DYS385. Individual haplotype data are available on line. A low degree of variation is present among regions. Use of this database is specifically recommended for forensic applications in Italy.

Characterization of pseudoxanthoma elasticum-like lesions in the skin of patients with beta-thalassemia.

BACKGROUND: Pseudoxanthoma elasticum (PXE), an inherited disorder of unknown pathogenesis, is characterized by elastic fiber mineralization, collagen fibril alterations, and accumulation of thread material in the extracellular space. PXE-like clinical lesions have been described in patients with beta-thalassemia. OBJECTIVE AND METHODS: Dermal lesions in these two genetic disorders were compared by light and electron microscopy and by immunocytochemistry. RESULTS: In both disorders, elastic fiber polymorphism, fragmentation, and mineralization were structurally identical. Elastic fiber mineralization in beta-thalassemia was associated with vitronectin, bone sialoprotein, and alkaline phosphatase, similar to what was observed in inherited PXE. Furthermore, abnormalities of collagen fibrils and filament aggregates were identical in both disorders. In both inherited and beta-thalassemia-associated PXE, unrelated gene defects seem to induce cell metabolic abnormalities that lead to identical clinical and structural phenotypes. CONCLUSION: Data indicate that patients with beta-thalassemia may undergo important alterations of connective tissues, a better understanding of which may help in preventing clinical complications.