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In sexual-assault cases, autosomal DNA analysis of gynecological swabs is a challenge, as the presence of a large quantity of female material may prevent detection of the male DNA. A solution to this problem is differential DNA extraction, but there is no established best practice for this. We decided to test the efficacy of a number of different protocols on simulated casework samples. Four difficult samples were sent to the nine Swiss laboratories active in forensic genetics. In each laboratory, staff used their routine protocols to separate the epithelial-cell fraction, enriched with the non-sperm DNA, from the sperm fraction. DNA extracts were then sent to the organizing laboratory for analysis. Estimates of male:female DNA ratio without differential DNA extraction ranged from 1:38 to 1:339, depending on the semen used to prepare the samples. After differential DNA extraction, most of the ratios ranged from 1:12 to 9:1, allowing detection of the male DNA. Compared with direct DNA extraction, cell separation resulted in losses of 94-98% of the male DNA. As expected, more male DNA was generally present in the sperm than in the epithelial-cell fraction. However, for about 30% of the samples, the reverse trend was seen. The recovery of male and female DNA was highly variable, depending on the laboratory involved. An experimental design similar to the one used in this study may be of assistance for local protocol testing and improvement.

In this paper, capillary electrophoresis in clinical and forensic analysis is reviewed on the basis of the literature of 1999, 2000 and the first papers in 2001. An overview of progress relevant examples for each major field of application, namely (i) analysis of drug seizures, explosives residues, gunshot residues and inks, (ii) monitoring of drugs, endogenous small molecules and ions in biofluids and tissues, (iii) general screening for serum proteins and analysis of specific proteins (carbohydrate deficient transferrin, alpha1-antitrypsin, lipoproteins and hemoglobins) in biological fluids, and (iv) analysis of nucleic acids and oligonucleotides in biological samples, including oligonucleotide therapeutics, are presented.

We identified five patients with congenital secondary hypothyroidism with isolated thyrotropin (TSH) deficiency originating from three and two unrelated Argentinean and Swiss families, respectively. The affected patients presented with both low TSH as well as low thyroid hormone levels. Further, TSH-releasing hormone (TRH) stimulation failed to increase serum TSH, whereas prolactin increased adequately. These affected children were homozygous for a 1-bp deletion (822delT) in the TSH-beta subunit gene leading to a cysteine 105 to valine conversion (C105V) and to a frameshift with a premature stop codon at position 114 (C105Vfs114X). In a total of 22 families five different mutations located within the coding region of the TSH-beta subunit gene responsible for congenital secondary hypothyroidism have been reported so far (E12X; G29R; Q49X; IVS2 +5, G --> A; C105Vfs114X). Importantly, out of 13 families, including our five families, the C105Vfs114X mutation has been described in 12 unrelated and non-consanguineous families, whereas the remaining four TSH-beta subunit gene mutations have been described in consanguineous families only. Therefore the C105Vfs114X mutation within the TSH-beta subunit gene is the most frequent alteration causing congenital secondary hypothyroidism (13 of 22; 59%) and occurs mainly in unrelated and non-consanguineous families (12 of 13; 92%). As we could exclude a common ancestry by microsatellite marker analysis in our five independent families we concluded that the codon 105 in the TSH-beta subunit gene might be a "hot spot," although a founder effect has been reported in certain cases clustered in a highly specific and restricted geographical area.

Critical cytogenetic (re)evaluation of 2 of our own cases of tricho-rhino-phalangeal syndrome II (TRP II), or Langer-Giedion syndrome (LGS), and 10 cases from the literature, suggests that the shortest region of overlap of the 8q deletion is a part of band q24.1. This region is assumed to be causally related to this syndrome, and possibly also to TRP I syndrome which, therefore, may not be a causally separate entity.

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BackgroundProfiling sperm DNA present on vaginal swabs taken from rape victims often contributes to identifying and incarcerating rapists. Large amounts of the victim’s epithelial cells contaminate the sperm present on swabs, however, and complicate this process. The standard method for obtaining relatively pure sperm DNA from a vaginal swab is to digest the epithelial cells with Proteinase K in order to solubilize the victim’s DNA, and to then physically separate the soluble DNA from the intact sperm by pelleting the sperm, removing the victim’s fraction, and repeatedly washing the sperm pellet. An alternative approach that does not require washing steps is to digest with Proteinase K, pellet the sperm, remove the victim’s fraction, and then digest the residual victim’s DNA with a nuclease.MethodsThe nuclease approach has been commercialized in a product, the Erase Sperm Isolation Kit (PTC Labs, Columbia, MO, USA), and five crime laboratories have tested it on semen-spiked female buccal swabs in a direct comparison with their standard methods. Comparisons have also been performed on timed post-coital vaginal swabs and evidence collected from sexual assault cases.ResultsFor the semen-spiked buccal swabs, Erase outperformed the standard methods in all five laboratories and in most cases was able to provide a clean male profile from buccal swabs spiked with only 1,500 sperm. The vaginal swabs taken after consensual sex and the evidence collected from rape victims showed a similar pattern of Erase providing superior profiles.ConclusionsIn all samples tested, STR profiles of the male DNA fractions obtained with Erase were as good as or better than those obtained using the standard methods.