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Androgenetic alopecia, known in men as male pattern baldness (MPB), is a very conspicuous condition that is particularly frequent among European men and thus contributes markedly to variation in physical appearance traits amongst Europeans. Recent studies have revealed multiple genes and polymorphisms to be associated with susceptibility to MPB. In this study, 50 candidate SNPs for androgenetic alopecia were analyzed in order to verify their potential to predict MPB. Significant associations were confirmed for 29 SNPs from chromosomes X, 1, 5, 7, 18 and 20. A simple 5-SNP prediction model and an extended 20-SNP model were developed based on a discovery panel of 305 males from various European populations fitting one of two distinct phenotype categories. The first category consisted of men below 50 years of age with significant baldness and the second; men aged 50 years or older lacking baldness. The simple model comprised the five best predictors: rs5919324 near AR, rs1998076 in the 20p11 region, rs929626 in EBF1, rs12565727 in TARDBP and rs756853 in HDAC9. The extended prediction model added 15 SNPs from five genomic regions that improved overall prevalence-adjusted predictive accuracy measured by area under the receiver characteristic operating curve (AUC). Both models were evaluated for predictive accuracy using a test set of 300 males reflecting the general European population. Applying a 65% probability threshold, high prediction sensitivity of 87.1% but low specificity of 42.4% was obtained in men aged <50 years. In men aged ≥50, prediction sensitivity was slightly lower at 67.7% while specificity reached 90%. Overall, the AUC=0.761 calculated for men at or above 50 years of age indicates these SNPs offer considerable potential for the application of genetic tests to predict MPB patterns, adding a highly informative predictive system to the emerging field of forensic analysis of externally visible characteristics.

The European Forensic Genetics Network of Excellence (EUROFORGEN-NoE) undertook a collaborative project on mRNA-based body fluid/skin typing and the interpretation of the resulting RNA and DNA data. Although both body fluids and skin are composed of a variety of cell types with different functions and gene expression profiles, we refer to the procedure as 'cell type inference'. Nine laboratories participated in the project and used a 20-marker multiplex to analyse samples that were centrally prepared and thoroughly tested prior to shipment. Specimens of increasing complexity were assessed that ranged from reference PCR products, cDNAs of indicated or unnamed cell type source(s), to challenging mock casework stains. From this specimen set, information on the overall sensitivity and specificity of the various markers was obtained. In addition, the reliability of a scoring system for inference of cell types was assessed. This scoring system builds on replicate RNA analyses and the ratio observed/possible peaks for each cell type [1]. The results of the exercise support the usefulness of this scoring system. When interpreting the data obtained from the analysis of the mock casework stains, the participating laboratories were asked to integrate the DNA and RNA results and associate donor and cell type where possible. A large variation for the integrated interpretations of the DNA and RNA data was obtained including correct interpretations. We infer that with expertise in analysing RNA profiles, clear guidelines for data interpretation and awareness regarding potential pitfalls in associating donors and cell types, mRNA-based cell type inference can be implemented for forensic casework.

Forensic characterisation of organ tissue generally occurs through histological and immunological assays of limited sensitivity. Here, we explore an alternative approach and examine a total of 41 candidate mRNA markers for their ability to differentiate between brain, lung, liver, skeletal muscle, heart, kidney and skin. Various selection rounds are applied involving 85 organ tissues (36 excised autopsy specimens and 49 frozen tissue sections, with at least ten specimens for each organ type), 20 commercially available RNAs from different human tissues and at least two specimens of blood, saliva, semen, vaginal mucosa, menstrual secretion or touch samples. Finally, 14 markers are regarded tissue-specific and included in an endpoint RT-PCR multiplex together with one general muscle, one blood and one housekeeping marker. This 17-plex is successfully used to analyse a blind test set of 20 specimens including mixtures, and samples derived from stabbing of organ tissues. With the blind test set samples, it is shown that an earlier described interpretation strategy for RNA cell typing results [1] is also effective for tissue inference. As organ-typing is embedded in a procedure of combined DNA/RNA extraction and analysis, both donor and organ type information is derived from the same sample. Some autopsy specimens presented DNA profiles characteristic for degraded DNA. Nevertheless, the organ-typing multiplex could generate full RNA profiles, which is probably due to small sizes of the amplicons. This assay provides a novel tool for analysis of samples from violent crimes.