Congenital tetragametic blood chimerism explains a case of questionable paternity

Human chimerism is the presence of ≥ 2 cell populations in one person that contain genetic material from more than one zygote. Chimerism may be either acquired by transfusion or transplantation of donor cells, or congenital arising from embryo fusion or dizygotic twin-twin transfusion. We encountered a 4-year-old boy with developmental hip dysplasia whose preoperative (serologic) blood group was AB, but whose red cell agglutination was atypical ("mixed field") and caused us to study the patient's parents' ABO blood groups. Parental blood groups (AB and O) suggested possible nonparentage. An alternative explanation of the findings was that the child was chimeric or mosaic. Molecular cloning and genotyping of his ABO locus in leukocytes revealed two heterozygous genotypes: A102/O01 and B101/O01. Other loci, each of which possessed three distinct alleles, unambiguously showed transmission of two alleles from either the child's mother (e.g., HLA-A) or two alleles from the child's father (e.g., D8S1179). Findings indicate that the child is a tetragametic chimera.     

A search for obligatory paternal alleles in a DNA database to find an alleged rapist in a fatherless paternity case

Abstract: A sexual assault case resulted in a pregnancy, which was subsequently aborted. The alleged father of the fetus was unknown. Maternal and fetal types were obtained using the 11‐locus AmpF?STR^® SGM Plus^® kit. The national DNA database was searched for the paternal obligatory alleles and detected two suspects who could not be excluded as father of the male fetus. Additional typing using the AmpF?STR^® Minifiler^? kit, containing three additional autosomal loci, was not sufficient to exclude either suspect. Subsequent typing using the PowerPlex^® 16, containing four additional loci, and Y‐Filer^? kits resulted in excluding one suspect. Searching a database for paternal obligatory alleles can be fruitful, but is fraught with possible false positive results so that finding a match must be taken as only preliminary evidence.     

A single mutation in the FGA locus responsible for false homozygosities and discrepancies between commercial kits in an unusual paternity test case

We report an unusual paternity test case showing multiple peculiarities. Using AmpFlSTR Profiler Plus and AmpFlSTR Identifiler PCR Amplification kits, the alleged father and the two children were apparently homozygous at the FGA locus, but using the PowerPlex 16 kit the three individuals were found to be heterozygous. Drop-out was caused by a single mutation event in the presumptive binding site of the reverse primer. In addition, three inconsistencies were detected between the daughter and the alleged father among 18 STR markers. The occurrence of the rare null allele at the FGA locus and case history suggested that the true father was the brother of the alleged father. Furthermore, a single-step repeat maternal mutation was also detected at D16S539. This puzzling case was solved by using multiple analytical approaches, including the use of different primer pairs, the use of a high number of STR markers, and the characterization of the mutation causing the "null allele."     

国产试剂盒Goldeneye~(TM)20A在亲权鉴定中的应用评估

目的评估GoldeneyeTM20A试剂盒在亲权鉴定中的应用价值。方法应用GoldeneyeTM20A试剂盒对289宗亲权鉴定案例中的FTA卡血样本基因组DNA进行PCR扩增,扩增产物用ABI 3130xl遗传分析仪进行毛细管电泳,GeneMapper v3.2和GeneMarker HID软件进行基因分型及统计学分析,并与IdentifilerTM、SinofilerTM、PowerPlex16 3种试剂盒进行比较。结果采用GoldeneyeTM20A试剂盒,累积非父排除概率(CPE)为0.999 999 996,累积个人识别能力(CPD)达0.999 999 999 999 999 999 999 932 44,与目前常用的3种试剂盒相比较,GoldeneyeTM20A试剂盒在不排除的案例中具有更高的CPI值;在排除的案例中具有更多的排除指标。结论国产GoldeneyeTM20A试剂盒在亲权鉴定中有较高的应用价值。     

亲权指数和个体识别似然比计算软件的开发与应用

目的建立计算亲子鉴定亲权指数(PI)和个体识别似然比(LR)的计算软件。方法依据相关行业规范和文献中给出的计算方法,利用计算机语言Visual Basic 6.0编写程序。结果开发出适用于PI和LR的计算软件。结论该计算软件可以帮助工作人员提高计算效率,服务法医物证工作。     

A D19S433 primer binding site mutation and the frequency in Japanese of the silent allele it causes

Short tandem repeat studies are powerful tools for parentage analysis and for identification of missing persons, victims of murder, and victims of mass fatalities when reference samples are unavailable. The primer in the Identifiler kit failed to amplify an allele at the D19S433 locus, producing a silent ("null") allele. The causal mutation is a base change (G>A) 32 nucleotides downstream from the 3' end of the AAGG repeats. The silent alleles are problematical in parentage analysis because when transmitted, they can cause a parent-child inconsistency that is unrelated to Mendelian genetics. The inconsistency is sometimes termed an "apparent opposite homozygosity" and it produces false evidence of nonparentage. Alternative primers were designed to amplify the D19S433 locus alleles and they detect the silent allele. Frequencies of the (no longer) silent allele were determined to be 0.0114 in 176 people from Shizuoka (Honshu) and 0.0128 in 156 people from Okinawa.     

Differex~（TM）与Chelex-100法在混合斑检验中的应用比较

目的探讨DifferexTM系统法在法医学性侵犯案件混合斑检验中的应用价值,并与传统Chelex-100法进行比较。方法对日常性侵犯案件中的生物检材分别通过DifferexTM系统法与Chelex-100法检验来比较两种方法的优劣。结果采用Chelex-100法提取时,在所检验样本中仅有床单全部获得单一分型,而采用DifferexTM系统法则只有一条内裤的分型为混合型,其它均为单一分型。应用DifferexTM系统法还可以同时提取女性上皮细胞DNA,成功率为100%。采用Chelex-100法时出现双尖峰的频率也明显超过DifferexTM系统法。结论 DifferexTM系统法在法医学性侵犯案件混合斑检验中比Chelex-100法具有更明显的优势,是一种非常有应用前景的方法。     

Distribution of the AMPFLPs YNZ22, 3′APOB and COL2A1 in the population of Galicia (NW Spain)

Two different electrophoretic methods were used for typing three amplified fragment length polymorphisms (AMPFLPs), (3′ApoB, YNZ22 and COL2A1) in a Galician (NW Spain) population sample. Because of the problems of anomalous mobility for the 3′ApoB system and the intermediate alleles found in the COL2A1 system, the use of automated sequencers and denaturing conditions is recommended for typing these two systems. Nevertheless, simple electrophoretic methods, such as the PhastSystem, can be used for YNZ22 typing. Although intermediate COL2A1 alleles can be distinguished with the sequencers, a binning approach was adopted for comparison purposes. The population sampled was in Hardy-Weinberg equilibrium for the three systems using an exact test. This type of statistical analysis is more appropriate when the number of alleles in a system is high. No significant differences with other Caucasian populations were found for the three systems studied. The characteristics of the polymorphisms, shown by 3′ApoB, YNZ22 and COL2A1, reflected in the statistical parameters studied, demonstrate that these AMPFLPs are of considerable interest for forensic purposes.     

Haplotype frequencies of eight Y-chromosome short tandem repeats loci in four Amerindian populations (state of Hidalgo, Mexico)

Population: Amerindian populations: Huastecos (n=97), Otomies de la Sierra (n=41), Otomies del Valle (n=40), and Tepehuas (n=13).     

Influenza A/H1N1 (2009) Infection as a Cause of Unexpected Out‐of‐Hospital Death in the Young*

Abstract: In March 2009, a new strain of influenza A/H1N1 virus was identified in Mexico, responsible for a pandemic. Worldwide, more than 13,500 patients died, most often from acute respiratory distress syndrome. Because sudden death cases were rare, involving mostly young apparently healthy persons, influenza A/H1N1 (2009)‐related deaths may be misdiagnosed, which can raise medico‐legal issues. Case history: we report on an unexpected out‐of‐hospital death involving a young male with no past medical history and no vaccination. Fever was his only symptom. Laboratory tests: histology showed patchy necrotic foci with mononuclear inflammation in the lungs. The heart was histologically normal, but virological analyses using molecular biology on frozen myocardial samples showed high virus load. In conclusion, this case report shows that influenza A/H1N1 (2009) virus can be a cause of sudden cardiac death in the young and demonstrates the importance of quantitative virological analyses for the diagnosis of myocarditis.     

A case study on the application of isotope ratio mass spectrometry (IRMS) in determining the provenance of a rock used in an alleged nickel switching incident

The application of isotope ratio mass spectrometry (IRMS) in forensic science to establish the provenance of a range of questioned substances including soils, drugs, explosives, currency, ivory and rhino horn has been widely documented. The present study wishes to highlight the applicability of IRMS and specifically stable carbon IRMS in determining the provenance of a carbonate rock that was switched for nickel metal exported from South Africa to Israel. The technique employed effectively argued against a South African origin for the rock whilst simultaneously supporting an Israeli origin, enabling investigators to focus their attention accordingly. The study represents the first documented instance known to the authors where IRMS has been employed in the forensic geo-location of a rock.