Postmortem genetic analysis of 17 sudden cardiac deaths identified nonsense and frameshift variants in two cases of arrhythmogenic cardiomyopathy.

Sudden death, or unexpected natural death of a healthy individual, is a serious problem in all nations. Sudden cardiac death (SCD) mainly due to ischemic heart diseases is the top cause of sudden death. However, there are pathophysiological conditions, referred to as sudden arrhythmic death syndrome, in which no apparent lesion can be identified even after complete conventional or ordinary autopsy. While postmortem genetic analyses have accumulated evidence about underlying genetic abnormality in such cases, the precise relationships between genetic background and the phenotype have been largely elusive. In this study, a retrospective investigation of 17 autopsy cases in which lethal arrhythmia was suspected to be the cause of death was carried out. Genetic analysis focusing on 72 genes reported to be associated with cardiac dysfunctions was performed, in combination with detailed histopathological and postmortem imaging examination, and a family study. As a result, in two cases of suspected arrhythmogenic cardiomyopathy (ACM), we found a nonsense variant in PKP2 and frameshift variant in TRPM4 gene. In contrast, the other 15 cases showed no morphological changes in the heart despite the presence of a frameshift variant and several missense variants, leaving the clinical significance of these variants obscure. The findings of the present study suggest that nonsense and frameshift variants could be involved in the morphological abnormality in cases of SCD due to ACM, while missense variants alone rarely contribute to massive structural changes in the heart.

Acute subdural hematoma caused by rupture of a mycotic aneurysm due to meningitis associated with infectious endocarditis: comparison of autopsy findings with postmortem computed tomography.

Forensic pathologists often encounter cases of acute subdural hematoma (SDH) due to trauma, whereas those attributable to endogenous causes are rare. Here, we report a case of the latter type in a 42-year-old man who was found dead at home after several months of fever and malaise. Postmortem computed tomography (PMCT) and autopsy were undertaken to clarify the cause of death. PMCT images revealed a fatal SDH and a localized hyper-density area in the right parietal lobe; macroscopic and microscopic examinations revealed SDH due to rupture of a mycotic aneurysm (MA) associated with meningitis. The PMCT images also indicated thickening and calcification of the mitral valve, while autopsy demonstrated infective endocarditis (IE). In addition, PMCT demonstrated a low-density area in the spleen, which was shown to be a splenic abscess at autopsy. PMCT also demonstrated tooth cavities. Based on the findings of autopsy, the cause of death was considered to be SDH due to rupture of the MA resulting from meningitis with IE and splenic abscess. Although PMCT was unable to clarify the significance of any individual feature, a retrospective review of the PMCT images might have suggested IE, bacteremia, or ruptured MA leading to SDH. This case suggests that, instead of interpreting individual features demonstrated on PMCT images, integrated interpretation of overall PMCT findings might provide clues for identifying causes of death, despite the fact that PMCT lacks diagnostic accuracy for infectious diseases such as IE and meningitis.

Reduction of blood group A antigen on erythrocytes in a patient with myelodysplastic syndrome harboring somatic mutations in RUNX1 and GATA2.

BACKGROUND: Reduction of blood group ABO antigens on red blood cells (RBCs) is well known in patients with leukemias, and this reduction of ABO expression is strongly associated with DNA methylation of the ABO promoter. Previously, we reported a two-nucleotide deletion in RUNX1 encoding an abnormally elongated protein lacking the trans-activation domain in a patient with myelodysplastic syndrome (MDS) showing A-antigen loss on RBCs. This prompted us to investigate the underlying mechanism responsible for A-antigen reduction on RBCs in another patient with MDS. STUDY DESIGN AND METHODS: Screening of somatic mutations was carried out using a targeted sequencing panel with genomic DNA from peripheral blood mononuclear cells from the patient and eleven MDS controls without A- or B-antigen loss. DNA methylation of the ABO promoter was examined by bisulfite genomic sequencing. Transient transfection assays were performed for functional evaluation of mutations. RESULTS: Screening of somatic mutations showed missense mutations in RUNX1 and GATA2 in the patient, while no mutation was found in exons of those genes in the controls. There was no significant difference in ABO promoter methylation between the patient and the controls. Transient transfection experiments into COS-7 and K562 cells suggested that the amino acid substitutions encoded by those mutations reduced or lost the trans-activation potential of the ABO expression. CONCLUSION: Considering the discrepancy between the variant frequencies of these mutations and the ratios of the RBCs with A-antigens loss, the antigen reduction might be associated with these somatic mutations and hypermethylation of the ABO promoter.

High membrane expression of CMTM6 in hepatocellular carcinoma is associated with tumor recurrence.

CKLF-like MARVEL transmembrane domain-containing protein 6 (CMTM6) maintains membrane PD-L1 expression by controlling its endosomal recycling. However, in patients with hepatocellular carcinoma (HCC), the correlation among CMTM6, B7 family ligands, and CD8-positive cytotoxic T lymphocytes (CTLs), and the molecular function of CMTM6 in HCC have not been established. We performed immunohistochemistry to evaluate the relationships among CMTM6 expression, clinicopathological factors, B7 family ligands expression, and CTL infiltration in HCC samples. Moreover, we established CMTM6-knockout human HCC cell lines to evaluate the function of human CMTM6 in immune regulation and tumor viability. CMTM6 expression was positively associated with membrane B7 family ligands expression and CTL infiltration in HCC samples. High CMTM6 expression in HCC tissues was associated with the expression of the proliferation marker Ki-67 and shorter recurrence-free survival. In vitro analysis showed the downregulation of membrane B7 family ligands and proliferation potency in the CMTM6-knockout human HCC cell line. High membrane CMTM6 expression was associated with tumor recurrence and proliferation via the regulation of membranous B7 family ligands expression. Thus, CMTM6 might be a biomarker to predict the risk of HCC recurrence and a therapeutic target to suppress tumor growth and increase CTL activity.

RUNX1 mutation in a patient with myelodysplastic syndrome and decreased erythrocyte expression of blood group A antigen.

BACKGROUND: Loss of blood group ABO antigens on red blood cells (RBCs) is well known in patients with leukemias, and such decreased ABO expression has been reported to be strongly associated with hypermethylation of the ABO promoter. We investigated the underlying mechanism responsible for A-antigen reduction on RBCs in a patient with myelodysplastic syndrome. STUDY DESIGN AND METHODS: Genetic analysis of ABO was performed by PCR and sequencing using peripheral blood. RT-PCR were carried out using cDNA prepared from total bone marrow (BM) cells. Bisulfite genomic sequencing was performed using genomic DNA from BM cells. Screening of somatic mutations was carried out using a targeted sequencing panel with genomic DNA from BM cells, followed by transient transfection assays. RESULTS: Genetic analysis of ABO did not reveal any mutation in coding regions, splice sites, or regulatory regions. RT-PCR demonstrated reduction of A-transcripts when the patient's RBCs were not agglutinated by anti-A antibody and did not indicate any significant increase of alternative splicing products in the patient relative to the control. DNA methylation of the ABO promoter was not obvious in erythroid cells. Targeted sequencing identified somatic mutations in ASXL1, EZH2, RUNX1, and WT1. Experiments involving transient transfection into K562 cells showed that the expression of ABO was decreased by expression of the mutated RUNX1. CONCLUSION: Because the RUNX1 mutation encoded an abnormally elongated protein without a transactivation domain which could act as dominant negative inhibitor, this frame-shift mutation in RUNX1 may be a genetic candidate contributing to A-antigen loss on RBCs.

Novel Cardiocerebral Channelopathy Associated with a KCND3 V392I Mutation.

While a KCND3 V392I mutation uniquely displays a mixed electrophysiological phenotype of Kv4.3, only limited clinical information on the mutation carriers is available. We report two teenage siblings exhibiting both cardiac (early repolarization syndrome and paroxysmal atrial fibrillation) and cerebral phenotypes (epilepsy and intellectual disability), in whom we identified the KCND3 V392I mutation. We propose a link between the KCND3 mutation with a mixed electrophysiological phenotype and cardiocerebral phenotypes, which may be defined as a novel cardiocerebral channelopathy.

DNA methylation of the NR3C1 promoter region in brains of pediatric victims of physical abuse.

Early life stress (ELS) has been suggested to cause epigenetic changes to genes in the brain, such as the Nuclear Receptor Subfamily 3, Group C, Member 1 gene (NR3C1). Conversely, evaluation of the epigenetic status in the postmortem brain might provide clues to the antemortem ELS experience. We examined DNA methylation of the 1F promoter region of NR3C1 in the postmortem brains of eight children including four ELS cases. As a result, DNA methylation was evident in ELS cases due to severe physical abuse. Epigenetic status may have potential application as a biomarker for clarifying the antemortem experiences of deceased.

Epithelial Expression of Human ABO Blood Group Genes Is Dependent upon a Downstream Regulatory Element Functioning through an Epithelial Cell-specific Transcription Factor, Elf5.

The human ABO blood group system is of great importance in blood transfusion and organ transplantation. The ABO system is composed of complex carbohydrate structures that are biosynthesized by A- and B-transferases encoded by the ABO gene. However, the mechanisms regulating ABO gene expression in epithelial cells remain obscure. On the basis of DNase I-hypersensitive sites in and around ABO in epithelial cells, we prepared reporter plasmid constructs including these sites. Subsequent luciferase assays and histone modifications indicated a novel positive regulatory element, designated the +22.6-kb site, downstream from ABO, and this was shown to enhance ABO promoter activity in an epithelial cell-specific manner. Expression of ABO and B-antigen was reduced in gastric cancer KATOIII cells by biallelic deletion of the +22.6-kb site using the CRISPR/Cas9 system. Electrophoretic mobility shift assay and chromatin immunoprecipitation assay demonstrated that the site bound to an epithelial cell-specific transcription factor, Elf5. Mutation of the Ets binding motifs to abrogate binding of this factor reduced the regulatory activity of the +22.6-kb site. Furthermore, ELF5 knockdown with shRNA reduced both endogenous transcription from ABO and B-antigen expression in KATOIII cells. Thus, Elf5 appeared to be involved in the enhancer potential of the +22.6-kb site. These results support the contention that ABO expression is dependent upon a downstream positive regulatory element functioning through a tissue-restricted transcription factor, Elf5, in epithelial cells.

Histone deacetylase inhibitors suppress ABO transcription in vitro, leading to reduced expression of the antigens.

BACKGROUND: The ABO system is of fundamental importance in the fields of transfusion and transplantation and has apparent associations with certain diseases, including cardiovascular disorders. ABO expression is reduced in the late phase of erythroid differentiation in vitro, whereas histone deacetylase inhibitors (HDACIs) are known to promote cell differentiation. Therefore, whether or not HDACIs could reduce the amount of ABO transcripts and A or B antigens is an intriguing issue. STUDY DESIGN AND METHODS: Quantitative polymerase chain reactions were carried out for the ABO transcripts in erythroid-lineage K562 and epithelial-lineage KATOIII cells after incubation with HDACIs, such as sodium butyrate, panobinostat, vorinostat, and sodium valproate. Flow cytometric analysis was conducted to evaluate the amounts of antigen in KATOIII cells treated with panobinostat. Quantitative chromatin immunoprecipitation (ChIP) assays and luciferase assays were performed on both cell types to examine the mechanisms of ABO suppression. RESULTS: HDACIs reduced the ABO transcripts in both K562 and KATOIII cells, with panobinostat exerting the most significant effect. Flow cytometric analysis demonstrated a decrease in B-antigen expression on panobinostat-treated KATOIII cells. ChIP assays indicated that panobinostat altered the modification of histones in the transcriptional regulatory regions of ABO, and luciferase assays demonstrated reduced activity of these elements. CONCLUSION: ABO transcription seems to be regulated by an epigenetic mechanism. Panobinostat appears to suppress ABO transcription, reducing the amount of antigens on the surface of cultured cells.

Intestinal obstruction in a mentally retarded patient due to pica.

A 40-year-old mentally retarded Japanese man was admitted at rehabilitation facility for handicapped persons and found dead in his bed. His neonatal period was complicated by seizures, and he had a medical history of schizophrenia. A postmortem computed tomography scan suggested an intestinal obstruction, but the cause was unknown. To clarify the cause of death, a medicolegal autopsy was carried out. The gastrointestinal tract was found to contain copious amounts of cloth pieces. A diagnosis of intestinal obstruction secondary to pica of clothes was made. Despite still being an essentially neglect condition; mental retardation is cause to significant burden to the patient, his relatives and caregivers and the whole society. Moreover, people with mental retardation may be at increased risk for potentially self-injury due to ingestion of non-eating substance or incongruent intake of eating substances, which may on turn lead to severe or even life-threatening medical and surgical complications as herein reported. Specific attention also to pica in mentally-retarded patients with sudden, severe, gastrointestinal events, should therefore be placed in order to prevent potential death or otherwise severe chronic consequences, ideally aiming at enhancing the early recognition and multi-disciplinary management of those psychological stressors or triggers potentially responsible for pica too.

Expression of ABO blood-group genes is dependent upon an erythroid cell-specific regulatory element that is deleted in persons with the B(m) phenotype.

The ABO blood group is of great importance in blood transfusion and organ transplantation. However, the mechanisms regulating human ABO gene expression remain obscure. On the basis of DNase I-hypersensitive sites in and upstream of ABO in K562 cells, in the present study, we prepared reporter plasmid constructs including these sites. Subsequent luciferase assays indicated a novel positive regulatory element in intron 1. This element was shown to enhance ABO promoter activity in an erythroid cell-specific manner. Electrophoretic mobility-shift assays demonstrated that it bound to the tissue-restricted transcription factor GATA-1. Mutation of the GATA motifs to abrogate binding of this factor reduced the regulatory activity of the element. Therefore, GATA-1 appears to be involved in the cell-specific activity of the element. Furthermore, we found that a partial deletion in intron 1 involving the element was associated with B(m) phenotypes. Therefore, it is plausible that deletion of the erythroid cell-specific regulatory element could down-regulate transcription in the B(m) allele, leading to reduction of B-antigen expression in cells of erythroid lineage, but not in mucus-secreting cells. These results support the contention that the enhancer-like element in intron 1 of ABO has a significant function in erythroid cells.

Mutation of the GATA site in the erythroid cell-specific regulatory element of the ABO gene in a Bm subgroup individual.

BACKGROUND: The ABO blood group is important in blood transfusion. Recently, an erythroid cell-specific regulatory element has been identified in the first intron of ABO using luciferase reporter assays with K562 cells. The erythroid cell-specific regulatory activity of the element was dependent upon GATA-1 binding. In addition, partial deletion of Intron 1 including the element was observed in genomic DNAs obtained from 111 Bm and ABm individuals, except for one, whereas the deletion was never found among 1005 individuals with the common phenotypes. STUDY DESIGN AND METHODS: In this study, further investigation was performed to reveal the underlying mechanism responsible for reduction of B antigen expression in the exceptional Bm individual. Peptide nucleic acid-clamping polymerase chain reaction was carried out to amplify the B-related allele, followed by sequence determination. Electrophoretic mobility assays and promoter assays were performed to examine whether a nucleotide substitution reduced the binding of a transcription factor and induced loss of function of the element. RESULTS: Sequence determination revealed one point mutation of the GATA motif in the element. The electrophoretic mobility shift assays showed that the mutation abolished the binding of GATA transcription factors, and the promoter assays demonstrated complete loss of enhancer activity of the element. CONCLUSION: These observations suggest that the mutation in the GATA motif of the erythroid-specific regulatory element may diminish the binding of GATA transcription factors and down regulate transcriptional activity of the element on the B allele, leading to reduction of B antigen expression in erythroid lineage cells of the Bm individual.

Usefulness of virtual reassembly of the skull and spine in cases of fragmentation due to high-energy trauma: A feasibility study.

With the widespread use of postmortem computed tomography (PMCT) beside forensic autopsies for investigation of causes of death, three-dimensional (3D) reconstruction and fusion imaging using PMCT data are now becoming common. In the present study, the applicability of virtual reassembly from PMCT data was investigated in three cases involving fragmentation of the skull or spine due to high-energy trauma, as in such cases it is sometimes difficult to obtain detailed information on fractures using macroscopic observation alone. In the first case, virtual reassembly of the skull provided more information about the fractures than conventional reconstruction with adhesive. In the second case, although the skull was severely fractured and could not be examined macroscopically, virtual reassembly allowed detailed visualization of the fractures. In the last case, virtual reassembly of the spine helped to clarify that the 6th-8th thoracic vertebrae had been run over by a vehicle at the scene. Thus, virtual reassembly was shown to be useful for assessment of injury patterns, and event reconstruction.

Hypothermic death resulting from extreme freezing with characteristic postmortem computed tomography findings: A case report and review of the literature.

We report a case of hypothermic death that resulted from extreme freezing, with characteristic postmortem computed tomography (PMCT) findings. A 75-year-old man died in a deeply frozen state. In PMCT, there was a lack of increase in the bilateral lung-field attenuation. Urinary retention, with a hypodense area of frozen urine, was observed in the bladder. Changes that appeared to involve the crystallization of serum in frozen blood were observed in the aorta. Based on the scene and his circumstances, it was speculated that he died of hypothermia. Present case and our review revealed that although PMCT findings from hypothermic death that resulted from deep freezing are very rare, the characteristic PMCT findings may help determine the cause of death.

A novel genotyping method for rapid identification of the Le gene to select patients for diagnosis with CA19-9.

BACKGROUND: The antigenic determinant of CA19-9 is synthesized by the α1,3/4fucosyltransferase encoded by the Le gene in the Lewis blood group system. Accordingly, a diagnosis with CA19-9 is not appropriate forLe-negative patients who possess the Le gene-mutated le alleles homozygously. METHODS: A Le gene-specific PCR was undertaken to determine c59T>G by using a set of tag-sense and biotin-labeled anti-sense primers and a peptide nucleic acid-le-clamp which bound to G59 in the le alleles. Following mixing with streptavidin-coatedbluelatex beads, the PCR products were developed on a strip on which the complementary tag oligonucleotide to theLe gene-specific amplicon was immobilized. RESULTS: When the PCR products were developed on the strip, a clear line was rapidly observed in Le-positive but not in Le-negative individuals. In contrast, a significant number of cancer patients with Lewis-negative phenotype were found to possess CA19-9, while they were specifically genotyped asLe/-. No contradictory results were observed in cancer patients (n = 315) with respect to their Lewis genotypes and CA19-9 levels. CONCLUSIONS: c59T>G occurred commonly in the le alleles could be specifically and rapidly identified by the present method. This method appeared to be relevant forselecting cancer patientsto bediagnosed with CA19-9.

Emergence of an erythroid cell-specific regulatory region in ABO intron 1 attributable to A- or B-antigen expression on erythrocytes in Hominoidea.

A- and B-antigens are present on red blood cells (RBCs) as well as other cells and secretions in Hominoidea including humans and apes such as chimpanzees and gibbons, whereas expression of these antigens on RBCs is subtle in monkeys such as Japanese macaques. Previous studies have indicated that H-antigen expression has not completely developed on RBCs in monkeys. Such antigen expression requires the presence of H-antigen and A- or B-transferase expression in cells of erythroid lineage, although whether or not ABO gene regulation is associated with the difference of A- or B-antigen expression between Hominoidea and monkeys has not been examined. Since it has been suggested that ABO expression on human erythrocytes is dependent upon an erythroid cell-specific regulatory region or the + 5.8-kb site in intron 1, we compared the sequences of ABO intron 1 among non-human primates, and demonstrated the presence of sites orthologous to the + 5.8-kb site in chimpanzees and gibbons, and their absence in Japanese macaques. In addition, luciferase assays revealed that the former orthologues enhanced promoter activity, whereas the corresponding site in the latter did not. These results suggested that the A- or B-antigens on RBCs might be ascribed to emergence of the + 5.8-kb site or the corresponding regions in ABO through genetic evolution.

The malignant potential of pancreatic intraductal papillary mucinous neoplasm is reflected in expression levels of fucosylated glycans in α1 -acid glycoprotein.

BACKGROUND: Pancreatic intraductal papillary mucinous neoplasm (IPMN) involves multiple histopathological stages from benign to malignant lesions. Further, a biomarker to diagnose the malignant IPMN (IPMC) is clinically relevant. Recently, we found that serum fucosylated α1 -acid glycoprotein (fAGP) level markedly elevated along with disease progression in large cohorts of patients with various cancers. METHODS: The fAGP level was retrospectively analyzed in preoperative sera from 109 patients with IPMN, and the clinical relevance of fAGP was compared with currently available predictors as standard. RESULTS: The fAGP level in IPMC was found to be significantly higher than in benign IPMN (P = .0012). At a cutoff value of 27.04 U/µg, its sensitivity, specificity, and accuracy for IPMC were determined to be 83.61%, 65.96%, and 75.93%, respectively. Multivariate analyses revealed that the fAGP level was the only independent risk factor for predicting IPMC. Additionally, a combination of the fAGP level and 18 F-fluorodeoxyglucose uptake on the PET/CT imaging in the lesions seemed to offer the best diagnosis of IPMN. Accordingly, 27 of the 28 patients who were positive in both tests had IPMC, while patients who are negative had benign IPMN. CONCLUSIONS: The fAGP level appeared to be a relevant biomarker for malignant potential of IPMN.

Post-traumatic cerebral infarction caused by thrombus in the middle cerebral artery.

A woman in her 80s was found unconscious after being hit by a car while crossing a road. After admission to hospitals, computed tomography (CT) scans revealed traumatic brain injury (TBI), and the patient was treated symptomatically. However, despite improvement of TBI in CT images, she died unexpectedly. Postmortem CT demonstrated cerebral infarction in the territory of the right middle cerebral artery (MCA). Histopathological examination revealed lumen-obstructing thrombosis and intimal injury upstream of the thrombosis in the right MCA. These findings suggested that the intimal injury in the MCA had led to thrombus formation, and thromboembolism in the region distal to the injury leading to post-traumatic cerebral infarction (PTCI). Both postmortem CT and autopsy were able to reveal the final condition of the deceased, which had not been fully anticipated by the clinicians who had treated her after the accident. The longitudinal antemortem to postmortem course revealed by multiple CT images and the histopathological examination provided crucial clues to the pathogenesis of PTCI in this case.

Genetic and expression analysis of SNPs in the human deoxyribonuclease II: SNPs in the promoter region reduce its in vivo activity through decreased promoter activity.

Five SNPs in the human DNase II gene have been reported to be associated with rheumatoid arthritis (RA). Genotype and haplotype analysis of 14 SNPs, nine SNPs of which reported in the NCBI dbSNP database in addition to these five SNPs, was performed in healthy subjects. The enzymatic activities of the amino acid substituted DNase II corresponding to each SNP and serum DNase II in healthy Japanese, and promoter activities derived from each haplotype of the RA-related SNPs were measured. Significant correlations between genotype in each RA-related SNP and enzymatic activity levels were found; alleles associated with RA exhibited a reduction in serum DNase II activity. Furthermore, the promoter activities of each reporter construct corresponding to predominant haplotypes in three SNPs in the promoter region of the gene exhibited significant correlation with levels of serum DNase II activity. These findings indicate these three SNPs could alter the promoter activity of DNASE2, leading to a decline in DNase II activity in the serum through gene expression. Since the three SNPs in the promoter region of the DNase II gene could affect in vivo DNase II activity through reduction of the promoter activity, it is feasible to identify these SNPs susceptible to RA.