外显子组测序对1例青壮年猝死的分子遗传学分析CSCD

目的以1例青壮年不明原因猝死综合征(sudden unexplained death syndrome,SUDS)案例为研究对象,采用全外显子组测序技术,在全外显子组水平寻找与SUDS相关的致病基因突变。方法对1例常规尸体解剖及病理学检验未发现明显致死性病理改变的SUDS病例样本,利用Ion Torrent PGMTM系统进行全外显子组测序。测序数据以hg19为参照序列,并通过Phylo P、Poly Phen2、SIFT等软件进行突变功能分析。最后设置三重条件过滤筛选有意义的单核苷酸变异:选取错义突变-等位基因频率<1%-蛋白质功能预测。结果共发现4个罕见的可疑致病性单核苷酸变异。结合尸体解剖及病理学检验的结果,确定1个"高危害性"突变MYOM2(8_2054058_G/A)。Poly Phen2、SIFT的预测均为"有害"。结论利用二代测序技术进行全外显子组水平的基因突变检测和分析,可以为SUDS病例的死因分析提供新的方法和思路。MYOM2基因新可能是SUDS的致病基因,但其具体机制仍需进一步研究。     

外显子组测序对1例青壮年猝死的分子遗传学分析

目的以1例青壮年不明原因猝死综合征(sudden unexplained death syndrome,SUDS)案例为研究对象,采用全外显子组测序技术,在全外显子组水平寻找与SUDS相关的致病基因突变。方法对1例常规尸体解剖及病理学检验未发现明显致死性病理改变的SUDS病例样本,利用Ion Torrent PGMTM系统进行全外显子组测序。测序数据以hg19为参照序列,并通过Phylo P、Poly Phen2、SIFT等软件进行突变功能分析。最后设置三重条件过滤筛选有意义的单核苷酸变异:选取错义突变-等位基因频率1%-蛋白质功能预测。结果共发现4个罕见的可疑致病性单核苷酸变异。结合尸体解剖及病理学检验的结果,确定1个"高危害性"突变MYOM2(8_2054058_G/A)。Poly Phen2、SIFT的预测均为"有害"。结论利用二代测序技术进行全外显子组水平的基因突变检测和分析,可以为SUDS病例的死因分析提供新的方法和思路。MYOM2基因新可能是SUDS的致病基因,但其具体机制仍需进一步研究。     

肥厚型心肌病分子机制及法医病理学意义

肥厚型心肌病(hypertrophic cardiomyopathy,HCM)被证实是引发35岁以下青年人(尤其是运动员心源性猝死(sudden cardiac death,SCD)的首要原因。约60%的HCM患者由编码肌小节蛋白的基因突变导致,呈常染色体显性遗传模式。β肌球蛋白重链基因、肌球蛋白结合蛋白C基因、肌钙蛋白T基因、肌钙蛋白I基因被认为是引起HCM最常见的突变基因。基因检测在HCM的临床诊断中已趋于常态化,但在法医工作中应用较少,如果基因检测技术能够应用于法医病理学诊断,将会给HCM猝死案件的死亡原因确认工作提供便利。更重要的是,通过猝死者的基因检测结果尽早进行家庭成员的危险评估才能降低猝死的发生率。本文主要综述了HCM的分子机制进展以及该疾病在法医病理学诊断中的应用价值。     

中国汉族人群中Dia抗原和Dib抗原的分子遗传分析

目的研究中国汉族人群Diego血型系统中Dia和Dib抗原表达的分子遗传背景。方法采用血型血清学方法对2990例非血缘关系的捐血者进行Diego血型鉴定,从中随机选择20例表现型为Di(a-b )的样本,以及筛选到的所有Di(a b-)稀有血型样本,采用PCR-SSP、DNA直接测序方法分析Diego血型基因的分子遗传背景。结果2990例捐血者中,发现Di(a b-)表现型2例,Di(a b )167例,Di(a-b )2821例。随机选择的20例表现型为Di(a-b )的DNA样本,经PCR-SSP法检测的基因型为DI2DI2,对DI基因第19外显子直接测序,2561位上碱基为C。2例稀有血型Di(a b-)的DNA序列在19外显子2561位上碱基为T,基因型为DI1DI1。结论中国汉族人群Dia和Dib抗原表达的分子遗传基础是DI基因第19外显子2561位上碱基T-C的置换,引起第854位氨基酸的改变。     

中国汉族人群不明原因猝死与NOS1AP基因多态性的相关性

目的研究日常活动中不明原因猝死(sudden unexpected death,SUD)者NOS1AP基因的单核苷酸多态性。方法收集60例一般日常活动中SUD病例心血样本作为SUD组,另外随机抽取80例无关个体的外周血样本作为对照组,提取基因组DNA,用特异性引物对NOS1AP部分SNP位点(rs10494366、rs10918859、rs12143842、rs12742393、rs3751284、rs348624)进行PCR扩增和直接测序,计算等位基因频率和基因型频率,并分析各SNP位点在SUD组与对照组之间的差异性。结果 NOS1AP第6外显子区域的rs3751284位点的等位基因频率和基因型频率在两组人群中的差异均有统计学意义(P0.05)。rs3751284位点的最小等位基因的频率在SUD组为0.325,在对照组为0.475。结论 rs3751284位点可能是SUD的易感基因位点。     

青壮年猝死综合征SCN2B、SCN4B基因检测

目的寻找SCN2B、SCN4B基因的变异位点,探讨其与青壮年不明原因夜间睡眠中猝死(SMDS)的关系。方法提取SMDS病例组及健康对照组的基因组DNA,采用聚合酶链式反应(PCR)方法扩增SCN2B、SCN4B基因编码区外显子、外显子-内含子交界区以及3'侧翼区序列,直接行DNA测序以明确遗传变异类型。结果在病例组中共检测到4个变异位点,c.237+27AG,c.*38CT,c.174CT(p.C58C)和c.*7CT。结论本研究首次对中国人SMDS病例进行了SCN2B、SCN4B基因的检测,上述基因是否为中国人SMDS的易感基因尚有待进一步研究证实。     

窖蛋白基因变异及多态性与不明原因猝死的相关性CSCD

目的寻求窖蛋白(caveolin,CAV)基因变异位点,探讨其与不明原因猝死(sudden unexplained death,SUD)的相关性。方法收集SUD组(71例)、冠状动脉疾病(coronary artery disease,CAD)组(62例)和对照组(60例)血样,分别提取基因组DNA,采用PCR方法扩增CAV1与CAV3基因编码区及外显子-内含子拼接区,进行直接测序,以明确CAV基因的遗传变异类型,并进行统计学分析。结果在SUD组中共检测到4个可能有意义的变异位点,其中2个为新发现的突变位点,分别为CAV1:c.45C>T(T15T)和CAV1:c.512G>A(R171H);2个为SNP位点,分别为CAV1:c.246C>T(rs35242077)和CAV3:c.99C>T(rs1008642),且这两个SNP位点的基因型频率和等位基因频率在SUD组与对照组中差异具有统计学意义(P<0.05),在CAD组中均未发现上述变异位点。结论部分SUD可能与CAV1和CAV3基因变异存在一定相关性。     

窖蛋白基因变异及多态性与不明原因猝死的相关性

目的寻求窖蛋白(caveolin,CAV)基因变异位点,探讨其与不明原因猝死(sudden unexplained death,SUD)的相关性。方法收集SUD组(71例)、冠状动脉疾病(coronary artery disease,CAD)组(62例)和对照组(60例)血样,分别提取基因组DNA,采用PCR方法扩增CAV1与CAV3基因编码区及外显子-内含子拼接区,进行直接测序,以明确CAV基因的遗传变异类型,并进行统计学分析。结果在SUD组中共检测到4个可能有意义的变异位点,其中2个为新发现的突变位点,分别为CAV1:c.45CT(T15T)和CAV1:c.512GA(R171H);2个为SNP位点,分别为CAV1:c.246CT(rs35242077)和CAV3:c.99CT(rs1008642),且这两个SNP位点的基因型频率和等位基因频率在SUD组与对照组中差异具有统计学意义(P0.05),在CAD组中均未发现上述变异位点。结论部分SUD可能与CAV1和CAV3基因变异存在一定相关性。     

GPD1-L基因检测及其与青壮年猝死综合征的相关性

目的探寻甘油-3-磷酸脱氢酶样基因(glycerol-3-phosphate dehydrogenase 1 like gene,GPD1-L)的变异位点,讨论其与青壮年猝死综合征(sudden manhood death syndrome,SMDS)的关系。方法提取SMDS组及健康对照组血样的基因组DNA,采用PCR法扩增GPD1-L基因编码区外显子、外显子-内含子交界区以及3′侧翼区序列,直接进行DNA测序以明确遗传变异类型,并进行基因型频率和等位基因频率的统计学分析。结果在SMDS组中共检测到2个变异位点,c.465CT和c.*18GT,后者在SMDS组和对照组中基因型分布和等位基因频率存在一定差异,但无统计学意义(P0.05)。结论 GPD1-L基因变异与中国人SMDS发生的相关性尚有待进一步研究。     

遗传性心律失常猝死的分子解剖研究现状及展望

遗传性心律失常所致猝死的死因鉴定是法医病理学领域亟待解决的难题之一。近年来心律失常易感基因/突变的发现和高通量组学技术的推广,使得利用分子遗传学方法筛查猝死的遗传学病因（即＂分子解剖＂）成为可能。本文通过汇总心律失常分子遗传研究的进展,综述传统遗传分析和近期全基因组关联性研究（GWAS）筛查的结果,为心源性猝死的＂分子解剖＂研究提供候选基因列表;并进一步比较针对不明原因猝死所开展的回顾性＂分子解剖＂筛查的结果,探讨新技术在该领域的应用前景。这一综述有助于更好的认识心律失常所致猝死的分子机制,并为借助新一代遗传分析技术进行分子解剖提供有益参考。     

Presence of psychoactive substances in oral fluid from randomly selected drivers in Denmark

The aim of this investigation was to identify and characterise pathogenic mutations in a sudden cardiac death (SCD) cohort suspected of cardiomyopathy in persons aged 0-40 years. The study material for the genetic screening of cardiomyopathies consisted of 41 cases and was selected from the case database at the Institute of Forensic Medicine. Mutational screening by DNA sequencing was performed to detect mutations in DNA samples from deceased persons suspected of suffering from hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), and arrhythmogenic right ventricle cardiomyopathy (ARVC). A total of 9 of the examined 41 cases had a rare sequence variant in the MYBPC3, MYH7, LMNA, PKP2 or TMEM43 genes, of which 4 cases (9.8%) were presumed to be pathogenic mutations. The presumed pathogenic mutations were distributed with one case of suspected HCM and DCM (MYH7; p.R442H), one case of suspected DCM (LMNA; p.R471H), and two cases of suspected ARVC (PKP2; p.R79X and LMNA; p.R644C). The presented data adds important information on the genetic elements of SCD in the young, and calls for expert pathological evaluation and molecular autopsy in the post-mortem examination of SCD victims with structural anomalies of the heart.     

Postmortem genetic testing in sudden unexplained death: A public health laboratory experience

Sudden unexplained death in the young poses a diagnostically challenging situation for practicing autopsy pathologists, especially in the absence of anatomic and toxicological findings. Postmortem genetic testing may identify pathogenic variants in the deceased of such cases, including those associated with arrhythmogenic channelopathies and cardiomyopathies. The Wisconsin State Laboratory of Hygiene (WSLH) is a state-run public health laboratory which performs postmortem genetic testing at no cost to Wisconsin medical examiners and coroners. The current study examines sequencing data from 18 deceased patients (ages 2 months to 49 years, 5 females) submitted to WSLH, from 2016 to 2021. Panel-based analysis was performed on 10 cases, and whole exome sequencing was performed on the most recent 8 cases. Genetic variants were identified in 14 of 18 decedents (77.8%), including 7 with pathogenic or likely pathogenic variants (38.9%). Whole exome sequencing was more likely to yield a positive result, more variants per decedent, and a larger number of variants of uncertain significance. While panel-based testing may offer definitive pathogenic variants in some cases, less frequent variants may be excluded. Whole exome testing may identify rare variants missed by panels, but increased yield of variants of uncertain significance may be difficult to interpret. Postmortem genetic testing in young decedents of sudden unexplained death can provide invaluable information to autopsy pathologists to establish accurate cause and manner of death and to decedent's relatives to allow appropriate management. A public health laboratory model may be a financially advisable alternative to commercial laboratories for medical examiner's/coroner's offices.     

Sarcomeric gene mutations in sudden infant death syndrome (SIDS)

In developed countries, sudden infant death syndrome (SIDS) represents the most prevalent cause of death in children between 1 month and 1 year of age. SIDS is a diagnosis of exclusion, a negative autopsy which requires the absence of structural organ disease. Although investigators have confirmed that a significant percentage of SIDS cases are actually channelopathies, no data have been made available as to whether other sudden cardiac death-associated diseases, such as hypertrophic cardiomyopathy (HCM), could be responsible for some cases of SIDS. The presence of a genetic mutation in the sarcomeric protein usually affects the force of contraction of the myocyte, whose weakness is compensated with progressive hypertrophy and disarray. However, it is unclear whether in the most incipient forms, that is, first years of life, the lack of these phenotypes still confers a risk of arrhythmogenesis. The main goal of the present study is to wonder whether genetic defects in the sarcomeric proteins, previously associated with HCM, could be responsible for SIDS. We have analysed 286 SIDS cases for the most common genes implicated in HCM in adults. A total of 680 mutations localised in 16 genes were analysed by semi-automated matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDITOF-MS) using the Sequenom MassARRAY(?) System. Ten subjects with completely normal hearts showed mutated alleles at nine of the genetic variants analysed, and one additional novel mutation was detected by conventional sequencing. Therefore, a genetic mutation associated with HCM may cause sudden cardiac death in the absence of an identifiable phenotype.     

Iatrogenic deaths following treatment for hypertrophic obstructive cardiomyopathy: case reports and an approach to the autopsy and death certification

Hypertrophic cardiomyopathy (HCM) is a disease process which results in a large, heavy heart, with hypertrophy of the interventricular septum (IVS) and left ventricle. HCM accounts for a significant number of cases of sudden cardiac death each year, most infamously in young athletes. The prevalence of the disease has increased over the past several years due to advances in clinical diagnosis and molecular genetic studies. Over this same period, new forms of treatment also have emerged. One such treatment is alcohol septal ablation (ASA). ASA is a procedure performed by a cardiologist, via cardiac catheterization, by injecting pure ethanol into selected arteries which supply the IVS, resulting in a targeted myocardial infarction. This infarct then retracts and forms a scar, decreasing the outflow obstruction and improving the patient's clinical symptoms.The authors report 2 cases of death following ASA treatment of HCM. The first, a 56-year-old male, had his ASA procedure 10 days prior to death. The second decedent, a 76-year-old female, had her procedure only 30 hours before death. These case reports are followed by a discussion about HCM, including pathology, treatments, and treatment-related pathology, before closing with a discussion about death certification in the cases presented and therapy-related deaths in general.     

基于化学计量法的FTIR鉴别心源性猝死

目的联合应用傅里叶变换红外光谱技术及化学计量法对心源性猝死的大鼠进行鉴别分析。方法注射药物或空气分别诱导大鼠的心源性猝死及空气栓塞死亡模型。应用Nicolet i Z10 FTIR光谱仪采集血清样本的红外光谱,联合OMNIC及Unscrambler软件,基于光谱不同分子吸收区间建立偏最小二乘回归模型。结果基于指纹区(1 200~900cm-1)建立PLS模型,均方根误差和决定系数分别是0.068 3、0.981 3,预测均方根偏差和预测决定系数分别是0.104 8、0.956 1;基于蛋白质酰胺区间(1 720~1 480cm-1)建立PLS模型,RMSE和R2分别是0.058 6,0.986 2,RMSEP和预测R~2分别是0.079 4、0.974 7。综合分析两种模型,蛋白质酰胺区间的RMSEP更小,且预测R2更大,提示其预测效果略好于指纹区间。结论联合FTIR及化学计量法,基于蛋白质及指纹区的分子特征均可有效鉴别大鼠的心源性猝死,其中两种不同死因引起的蛋白质差异更为显著。     

大鼠心肌缺血后SERCA和PLB基因表达变化的观察

目的观察大鼠心肌缺血后，肌浆网钙调节蛋白SERCA和PLB基因表达水平变化，探讨其在早期心肌缺血诊断上的应用价值。方法25只大鼠随机分为正常对照组、缺血5、10、15min及缺血性猝死组，建立大鼠急性心肌缺血模型；利用荧光标记逆转录聚合酶链反应技术（RT—PCR）检测不同时间大鼠心肌缺血后，SERCA和PLB的基因表达变化，并与缺血性猝死组相比较。结果心肌缺血5min即可检测到SERCA和PLBmRNA表达相对下降，且随着缺血时间的延长，呈逐渐下降趋势，心肌缺血组与缺血性猝死组表达存在显著性差异。结论大鼠心肌缺血后SERCA和PLB基因表达变化呈一定规律性。对早期心肌缺血的诊断具有法医学意义。     

过敏性猝死者咽喉和胃肠组织内P物质的表达

目的观察P物质在过敏性猝死人体咽喉和胃肠组织的表达,并探讨其在法医学鉴定中的作用和意义。方法应用免疫组化方法对15例过敏性猝死者咽喉和胃肠组织的P物质表达进行研究,同时以冠心病猝死者作为对照;应用计算机图像分析系统对免疫组化染色结果进行分析,计算阳性指数(PI)。结果与对照组相比,实验组咽喉和胃肠组织P物质表达明显增加(P<0.001)。结论咽喉和胃肠组织的P物质表达可作为过敏性猝死的法医学鉴定的形态学依据和参考指标。     

Differentiating cause-of-death terminology for deaths coded as sudden infant death syndrome, accidental suffocation, and unknown cause: an investigation using US death certificates, 2003-2004

We compared written text on infant death certificates for deaths coded as sudden infant death syndrome (R95), unknown cause (R99), and accidental suffocation (W75). Using US mortality files supplemented with the death certifiers' written text for all infant deaths with International Classification of Diseases (ICD)-10 assigned codes R95, R99, and W75, we formed cause-of-death subcategories from common themes identified from the written text. Among all infant deaths in 2003-2004, the underlying cause of death was listed as R99 for 2128 deaths, R95 for 4408 deaths, and W75 for 931 deaths. Among the postneonatal deaths, the differences in subcategories varied between assigned ICD-10 codes: for R99-coded deaths, 45.8% were categorized as "Unknown" and 48.6% as "Pending"; for R95-coded deaths, 67.7% were categorized as "sudden infant death syndrome (SIDS)"; and for W75-coded deaths, 76.4% were categorized as "Suffocation." Examination of the written text on the death certificates demonstrates variability in the assigned ICD-10 codes which could have an important effect on the estimates of SIDS cases in the United States.     

类胰蛋白酶和IgE测定在过敏性猝死诊断中的应用研究

目的探讨过敏性猝死法医学鉴定的诊断方法和指标。方法采取10例正常人、9例过敏性猝死和19例其他死因（排除过敏反应、冠心病）尸体的静脉血，采用荧光酶联免疫法（Pharmacia UniCAP100过敏原定量分析仪）和酶联免疫吸附试验ELISA法分别测定血清肥大细胞类胰蛋白酶和]gE含量，采用免疫组化方法观察过敏性猝死和其他死因的肺组织中的肥大细胞类胰蛋白酶免疫组化染色。结果过敏性猝死者的血清类胰蛋白酶和IgE含量升高，与其他死因之间的差异具有显著性意义（P〈0．01），其他死因和正常人之间的差异无统计学意义（P〉0．05）；与其它死因相比，过敏性猝死肺组织中的肥大细胞类胰蛋白酶免疫组化阳性染色增强（P〈0．01）。结论过敏性猝死者血清IgE和肥大细胞类胰蛋白酶含量显著升高；过敏性猝死者肺组织中肥大细胞类胰蛋白酶染色增强。     

二维红外光谱用于急性心肌缺血猝死的鉴别研究

目的采用衰减全反射-傅里叶变换红外光谱(ATR-FTIR)技术检测急性心肌缺血猝死大鼠的血清分子特征,探讨二维红外光谱鉴别急性心肌缺血猝死的法医学价值。方法成年雄性SD大鼠随机分为急性心肌缺血猝死组(实验组)和空气栓塞死组(对照组),血清样本行ATR-FTIR检测,应用OMNIC软件进行光谱预处理并求二阶导数光谱,分别计算两组原始光谱及二阶导数光谱的相似度,并应用Matlab R2010a软件建立二维光谱模型。结果实验组与对照组的大鼠血清的原始红外光谱在峰形、峰位、峰强度均极其相似,相似度达99.78%,二阶导数光谱显示出两者相似度降至98.62%,二维光谱模型显示两组光谱在1 625cm~(-1)、1 550cm~(-1)、1 080cm~(-1)及860cm~(-1)附近的成分差异,且它们的自动峰个数不相同,提示两组在蛋白质、糖原、核酸等分子含量存在较明显差异。结论仅从一维光谱上难以区分出两组的分子差异,二维红外光谱可以直观、有效地反映出急性心肌缺血猝死与空气栓塞死的大鼠血清分子差异,有望应用于法医学死因鉴别。