Rare (uro-)genital pathologies in young girls mimicking sexual abuse

Examinations of young children for suspicions of sexual abuse are challenging for the involved medical specialists because the consequences of the interpretation of the findings can be severe and dramatic. A broad knowledge of differential diagnoses including rare pathologies like urethral prolapse and failure of the midline fusion of the perineum, known as perineal groove, is essential in order to avoid unnecessary diagnostics and treatment, prejudgment, and to reduce patient family’s anxiety. We report two independent cases of girls aged 7 months and 5 years suffering from these rare pathologies, one presenting with painless lower genital tract bleeding, the other showing a lesion of the perineum as random finding during a neuropediatrician’s consultation. In both cases, the pathologies were initially misdiagnosed as injuries due to sexual assault, and judicial investigation procedures were initiated. In this paper, the characteristic symptoms and morphology of urethral prolapse and perineal groove are presented to enhance the awareness of these pathologies among forensic experts and help to establish the correct diagnosis.

     

Inhibitory influences on receptive field size in the dorsal column nuclei

 Receptive fields (RFs) of neurons in the dorsal column nuclei (DCN) expand within minutes after the RFs are anesthetized via subcutaneous lidocaine injections (e.g., Pettit and Schwark). The mechanism of this rapid reorganization is of great interest. It has been proposed that such RF expansion results from a decline in inhibition within the DCN that unmasks previously ineffective synapses. To study the role of GABAergic inhibition in the DCN in controlling RF size, we applied by iontophoresis bicuculline methiodide to block γ-aminobutyric acid_A (GABA_A) receptors and 2-OH-saclofen to block GABA_B receptors. Blockade of GABA_A receptors resulted in RF expansions in 79% of the neurons, while blockade of GABA_B receptors resulted in RF expansions in 53% of the neurons. The effectiveness of receptor blockade in producing RF expansion was not related to neuronal response characteristics. Glutamate application resulted in RF expansions in only 2 of 23 neurons tested, suggesting that RF expansion was not simply due to increased excitability. The modality and adaptation characteristics of the expanded portions of the RFs were similar to those of the original RF. The results of the present study suggest that GABAergic inhibition can play a role in controlling RF size in the DCN, and that both GABA_A and GABA_B receptors may be involved in this process. Received: 12 November 1998 / Accepted: 27 January 1999     

Genetic identification of highly putrefied bodies using DNA from soft tissues

The identification of putrefied bodies is a common task in forensic routine work. The deceased are usually identified by dental records, fingerprinting, or—in cases were no such data are available—DNA analysis. However, with progressive putrefaction, DNA integrity is rapidly decreasing. Genetic analysis may then be greatly impaired, if not impossible. The aim of our study was to establish an efficient procedure to successfully extract and amplify DNA from soft tissues of bodies in different stages of putrefaction. Soft tissues—unlike teeth or bones—usually allow the application of fast and easy-to-use extraction protocols. DNA was extracted from different tissues (aorta, kidney, liver, and skeletal muscle) taken at autopsy using a commercially available DNA extraction kit, and DNA quality and quantity were controlled by agarose gel electrophoresis and real-time polymerase chain reaction (PCR). Presence of mitochondrial DNA was tested using a highly sensitive duplex PCR. Short tandem repeat analysis was done using the AmpFlSTR Identifiler kit. Additionally, mitochondrial DNA sequencing was performed. After DNA extraction from at least two different tissues—preferably the kidney and the aorta—with the extraction kit based on the Nucleobond method, a successful amplification of at least eight loci was possible in 17 out of 18 cases, and 12 or more loci could be amplified in 15 cases.     

The SNPforID Assay as a Supplementary Method in Kinship and Trace Analysis

Objective

Short tandem repeat (STR) analysis using commercial multiplex PCR kits is the method of choice for kinship testing and trace analysis. However, under certain circumstances (deficiency testing, mutations, minute DNA amounts), STRs alone may not suffice.

Methods

We present a 50-plex single nucleotide polymorphism (SNP) assay based on the SNPs chosen by the SNPforID consortium as an additional method for paternity and for trace analysis. The new assay was applied to selected routine paternity and trace cases from our laboratory.

Results and Conclusions

Our investigation shows that the new SNP multiplex assay is a valuable method to supplement STR analysis, and is a powerful means to solve complicated genetic analyses.     

The new guidelines for paternity analysis in Germany—how many STR loci are necessary when investigating duo cases?

The requirements in the new German guidelines for paternity analysis have not only changed according to the so-called Gendiagnostikgesetz, the new German law regulating human genetic as well as paternity analyses, but also regarding the minimal number of short tandem repeats (STRs) which should be investigated (15 STRs) and the minimal required average exclusion chance (99.999 %). Even in paternity analyses involving only two people (e.g., father and child or mother and child), this exclusion chance is mandatory. A retrospective analysis of 330 father–child cases from our routine investigations showed in 142 cases (43 %) an individual exclusion chance below 99.999 % when using 15 STRs as required, in our routine work provided by the Powerplex® 16 kit which is reported to have an average exclusion chance of 99.988 %. Therefore, these same 330 father–child pairs were additionally analysed using the Powerplex® 21 kit and 120 of these duos were additionally analysed using the Powerplex® ESX17 kit enabling the analysis of 20 or 16 loci respectively. Now, an individual exclusion chance of more than 99.999 % could be achieved in 95.5 % (Powerplex® 21; calculation without the results of D6S1043), 98.8 % (Powerplex® 21; calculation with the results of D6S1043, using allele frequencies established in this study for a German and a West African population) and 98.3 % (Powerplex® ESX17). These data clearly demonstrate that in duo cases, more than the required 15 STR loci have to be investigated to obtain sufficient results.     

Mitochondrial mutagenesis in the brain in forensic and pathological research

Accumulation of alterations to the mitochondrial DNA (mtDNA) would be expected to significantly impair the bioenergetic function of mitochondria in the affected host cells. Many of these changes have been associated with several specific diseases and the process of aging. These mutations may be the result of mitochondrial oxidative stress, which is increased with age of individuals and specific degenerative diseases. Our aim with this review is to summarize the recent literature on the occurrence of mtDNA alterations and its possible relation to age-depending degenerative processes with special regards to the brain. Additionally, we show how these alterations could be used in fields of pathology and forensic medicine.     

Methodical approach to brain hypoxia/ischemia as a fundamental problem in forensic neuropathology

A review is given summarizing different methods that have been applied to the specific forensic neuropathological question of brain hypoxia/ischemia. On the microscopic level the authors applied routine stains and immunohistochemistry (MAP2, ALZ 50, GFAP, CD68, beta-APP) for characterization of the functional activity of neurons as well as of different cell types in various brain areas. Moreover, using molecular techniques for evaluation of the mitochondrial 4977-bp deletion in correlation to hypoxia and to age brain tissue and single cell analyses are described. The demonstrated scope of methods and results give evidence of the wide spectrum of possibilities to visualize hypoxic brain injuries for determining the cause (and matter) of death and for reconstructing the time-dependent process.     

The use of different multiplex PCRs for twin zygosity determination and its application in forensic trace analysis

STR typing becomes more and more valuable for different approaches of science. It revolutionized determining of zygosity in twin research and it is very often the only possibility for discrimination in forensic trace analysis. In this study 55 twin pairs from Denmark were genetically investigated to determine their zygosity. For analysis two multiplex PCR kits, the AmpFlSTR Identifiler kit, which comprises 15 loci plus the amelogenin gender determination and the Powerplex ES kit with eight different loci were employed. For a forensic approach every twin pair was regarded as being a forensic trace analysis, i.e. suspect or victim/biological trace and then we determined the security and precision with that a match of genetic patterns or an exclusion could be observed. Sixty percent of the twin pairs were di- and 40% monozygotic. There were no differences in zygosity determination between the two multiplex kits. The lowest number of exclusions by determining dizygosity was four loci for the Identifiler and three for Powerplex ES kit, the highest was 13 (Identifiler) and eight (Powerplex). It could be shown that the highly discriminative multiplex PCR kits gave matching probabilities of over 99.999999% (calculation based on data for unrelated individuals) even when only five or six STRs could be determined (assuming a trace analysis with some non-detectable STRs and therefore an incomplete genetic pattern). No questionable results regarding zygosity of the twin pairs were obtained even when only eight loci (using the Powerplex ES kit) were investigated. The simulated forensic results showed that matching probabilities should always be handled with care to not possibly come to wrong conclusions concerning the origin of the biological trace.