人类可传播性海绵状脑病的流行及监测

可传播性海绵状脑病(Transmissible spongiformencephalopathies,TSE)是一类侵袭人类及多种动物中枢神经系统的退行性脑病,潜伏期长,100%病死率,目前已经在人类以及20余种动物中发现有自然发生或感染的TSE。人类的TSE,包括克-雅病(Creutzfeldt-Jacob disease,CJD)、致死性家族型失眠症(Fatal familial insomnia,FFI)、GSS综合征(Gerstmann-Straussler-Scheinker syndrome,GSS)、库鲁病(Kuru)及变异型CJD(variant CJD,vCJD)。其感染因子目前认为是一种不含有核酸、具有自我复制能力的感染性蛋白粒子-朊病毒(prion),因此此类…     

朊病毒病实验室生物安全风险控制特点分析

朊病毒病（prion disaese）或可传播性海绵状脑病（transmissible spongiform encephalopathies,TSEs）是一类侵袭人类及多种动物中枢神经系统的退行性脑病,潜伏期长,100％病死率.人类的朊病毒病有克-雅病（Creutzfeldt-Jacob disease,CJD）,包括散发型、家族遗传型、医源型、变异型CJD（variant CJD,vCJD）,另外还有库鲁病（Kuru）、GSS综合征（Gerstmann-Straussler-Scheinker syndrome）、致死性家族型失眠症（fatal familial insomnia,FFI）,其致病因子是朊病毒.朊病毒为微小的蛋白感染颗粒,不包含核酸,与常规病毒不同[1].目前认为朊病毒是由在正常哺乳动物脑组织中存在的PrP蛋白（PrPC）经过构象转变而形成,又称PrPSc.在朊病毒患者中枢神经组织中可以检出异常致病蛋白PrPSc的沉积[1],但不同的朊病毒病具有不同的特点,主要表现在临床特征、潜伏期、脑组织中prpsc的分布、脑组织损伤的特点、能否诱导淀粉样变化,以及朊病毒的分子特征等,具有明显的＆quot;毒株＆quot;差异.鉴于朊病毒不同于传统病毒,具有独特的实验室检测技术[2],因此存在独特的生物风险形式.本文从朊病毒病原学特点和常见实验检测技术方面分析朊病毒实验活动中的生物风险形式,并提出相应的预防措施.     

抗维生素D佝偻病PHEX基因突变分析

目的 研究10例家族性及非家族性(散发)抗维生素D佝偻病患者PHEX基因突变,初步探讨我国东北地区抗维生素D佝偻病患者PHEX基因突变的类型.方法 应用常规饱和酚-氯仿法提取基因组DNA,聚合酶链反应扩增PHEX基因22个外显子序列,DGGE方法结合测序检测突变.结果 3名患者检测出PHEX基因突变:患者(H11)检测出16外显子上游46 bp(T>C)突变;患者(H1,H2)检测出18外显子1861(C>T)(Gin621X)的无义突变.结论 PHEX基因突变是抗维生素D佝偻病的致病原因.检测到的这两种PHEX基因突变为国际上首次报道的新的突变类型.     

一个单纯家族性嗜铬细胞瘤家系的VHL基因突变筛查

目的检测一个单纯家族性嗜铬细胞瘤家系的VHL基因突变情况。方法对一个单纯家族性嗜铬细胞瘤家系进行VHL基因突变检测，抽取该家系5例患者及15名血缘亲属外周血基因组DNA，对VHL基因3个外显子进行PCR，产物进行DNA测序。结果该家系5例患者均检测出VHL基因第2外显子上第587位核苷酸A—C突变，该突变导致第125位编码氨基酸由组氨酸（H）转变为脯氨酸（P）。15名家系成员中筛查出7名成员为该突变基因携带者，B超检查发现1例为双侧肾上腺肿瘤，1例为右肾囊肿。该突变为首次报道。结论该嗜铬细胞瘤家系中检测到可能的致病突变，VHL基因检测可早期发现致病基因携带者，建议对单纯家族性嗜铬细胞瘤患者常规进行VHL基因突变筛查。     

中国人家族性腺瘤性息肉病的基因型与临床表型的关系分析

目的 分析中国人家族性腺瘤性息肉病(FAP)的基因型与表现型的相关关系。 方法 14个经过了APC基因胚系突变检测的FAP家系患者,将所发现的APC基因胚系突变类型与临床特征进行综合分析。结果 位于密码子443、779、1062、1068、1309、1308、1394、c.657+1和c.532-2 微小突变的患者均表现为密集型息肉病,2例大片段缺失的患者表现为中间型息肉病,3例APC基因突变阴性的患者中2例表现为中间型息肉,1例表现为衰减型息肉病, 结论 中国人密集型息肉病APC基因突变范围较西方报道的位于密码子1250~1464之间广。     

山东半岛地区家族性和早发性乳腺癌BRCA2基因突变研究

目的 研究山东半岛地区家族性和早发性乳腺癌中乳腺癌易感基因BRCA2的突变位点及携带情况.方法 应用PureGene DNA纯化系统提取52例家族性和早发性乳腺癌患者的外周血单核细胞DNA,对BRCA2基因的全部编码序列及内含子和外显子拼接区进行扩增,扩增产物用变性高效液相色谱进行初筛,对发现异常片段经重新扩增后进行DNA测序证实.结果 在52例乳腺癌患者中发现3个(5.8%)BRCA2的致病性突变(2001delTTAT,4099＞T,5873C＞A).其中,家族性乳腺癌突变率达到12%(3/25),在单纯早发性乳腺癌病例中未发现致病性突变.结论 在家族性乳腺癌患者中,BRCA2基因突变可能具有重要作用,在此人群中有必要进行相关的基因检测.     

家族性慢性良性天疱疮一家系ATP2C1基因突变筛查

目的 对家族性慢性良性天疱疮一家系的ATP2C1基因突变进行检测.方法 采用聚合酶链反应扩增该家系4例患者和80名健康对照个体ATP2C1基因的全部外显子,直接测序法进行DNA测序,80名健康对照者为无亲缘关系的正常人.结果 在该家系所有患者中均检测出ATP2C1基因第163位碱基由C突变为T,导致终止密码子的提前出现.该突变位点在该家系正常人及健康对照人群中皆未发现.结论 该突变可影响ATP2C1基因的转录和翻译,在中国汉族人家族性慢性良性天疱疮家系中首次报道.     

新疆3个HCM家系MYH7基因突变DHPLC检测和DNA测序结果分析

目的 研究家族性肥厚型心肌病(HCM)的主要致病基因β肌球蛋白重链,MYH7突变情况.方法 用变性高效液相色谱DHPLC检测和DNA测序方法对3个HCM家系成员的MYH7基因8、14外显子及附近上下游序列进行检测分析.结果 3个家系其中1个家系发现MYH7基因14外显子中存在Thr441Met突变,该突变在中国人中是首次发现,此外外显子8也存在1个点突变.另外两个家系也发现有不同位点的突变.结论 运用变性高效液相色谱技术和DNA直接测序技术能实现对家族性肥厚型心肌病MYH7基因突变的筛查,有利于早期诊断、患病风险预测.     

家族性先天性珊瑚状白内障患者基因突变筛查

目的 检测一家系3例先天性珊瑚状白内障患者相关基因的致病性突变位点.方法 对一家系3例患者及4名正常家族成员进行了详细的病史采集和常规眼科检查,采血从白细胞中提取基因组DNA,PCR扩增功能候选基因或基因片段,直接双向测序,Blast比对筛查突变.结果 CRYAA、CRYAB、CRYBB2的第6外显子、CRYGD、CRYGC、GJA8、GJA,和MIP基因测序结果除发现了已经报道的单核苷酸多态性(single nucleotide polymorphism,SNP)外未发现致病性基因突变.结论 该家族患者并非由CRYGD以及其他的常见先天性白内障功能候选基因的已知突变引起,证实珊瑚状白内障存在遗传异质性.     

阳泉地区非综合征性耳聋患者常见耳聋基因突变的分析

目的通过对阳泉市盲聋哑学校69例耳聋患者进行GJB2、PDS及线粒体DNA基因热点突变筛查,分析该地区耳聋的突变分布及分子病因。方法收集山西省阳泉市69例耳聋患者,对所有患者线粒体DNAA1555G／C1494T、GJB2基因、PDS基因第7、8和19外显子进行扩增及测序。结果69例非综合征性耳聋患者共有60例检测到基因突变,突变率为86．96％（60／69）。57例患者检出GJB2基因突变,检出率达82．61％（57／69）,其中C．235delC突变率为10．14％;3例患者有PDS基因突变,分别为c．2168A〉G l例,IVS7-2G〉A 2例;未检测到线粒体DNAA1555G／C1494T突变。结论山西省阳泉市常见耳聋基因突变以GJB2基因突变率较高,为耳聋的诊断与治疗提供依据。     

Fatal familial insomnia, a prion disease with a mutation at codon 178 of the prion protein gene.

BACKGROUND. We previously described two members of a family affected by an apparently genetically determined fatal disease characterized clinically by progressive insomnia, dysautonomia, and motor signs and characterized pathologically by severe atrophy of the anterior ventral and mediodorsal thalamic nuclei. Five other family members who died of this disease, which we termed "fatal familial insomnia," had broader neuropathologic changes suggesting that fatal familial insomnia could be a prion disease. METHODS. We used antibodies to prion protein (PrP) to perform dot and Western blot analyses, with and without proteinase K, on brain tissue obtained at autopsy from two patients with fatal familial insomnia, three patients with sporadic Creutzfeldt-Jakob disease, and six control subjects. The coding region of the PrP gene was amplified and sequenced in the samples from the two patients with fatal familial insomnia. Restriction-enzyme analysis was carried out with amplified PrP DNA from 33 members of the kindred. RESULTS. Protease-resistant PrP was found in both patients with fatal familial insomnia, but the size and number of protease-resistant fragments differed from those in Creutzfeldt-Jakob disease. In the family with fatal familial insomnia, all 4 affected members and 11 of the 29 unaffected members had a point mutation in PrP codon 178 that results in the substitution of asparagine for aspartic acid and elimination of the Tth111 I restriction site. Linkage analysis showed a close relation between the point mutation and the disease (maximal lod score, 3.4 when theta was zero). CONCLUSIONS. Fatal familial insomnia is a prion disease with a mutation in codon 178 of the PrP gene, but the disease phenotype seems to differ from that of previously described kindreds with the same point mutation.     

Clinical,histopathological and genetic studies in a case of fatal familial insomnia with review of the literature

To explore clinical, histopathological and genetic features of a case with fatal familial insomnia (FFI) and review the related literatures. A middle-aged woman who complained of “insomnia for 9 months and psychosis for 3 months” was suspicious of FFI. The clinical features of the patient were analyzed, and the dead patient was examined by autopsy and the brain tissues were obtained for histopathological studies, and the blood samples from the patient and some of her familial members were collected for the sequencing of prion protein gene (PRNP). The main clinical features included intractable insomnia, psychiatric symptoms and abnormal night sleep behavior, unsteady gait, difficulty swallowing, sudden death, and positive family history. The pathological studies showed neuronal loss and gliosis of multiple brain tissues in the proband, predominated with thalamus; and analysis of PRNP revealed gene D178N mutation, and linkage with 129 methionine (Met) allele in the proband and a relative. FFI patients may manifest as sudden death, and may have prominent psychiatric symptoms; the corresponding gene mutation could occur in the asymptomatic carriers; the data of autopsy and brain tissue pathology is helpful for further understanding of this disease.     

The Priori Diseases

The human prion diseases are fatal neurodegenerative maladies that may present as sporadic, genetic, or infectious illnesses. The sporadic form is called Creutzfeldt-Jakob disease (CJD) while the inherited disorders are called familial (f) CJD, Gerstmann-Sträussler-Scheinker (GSS) disease and fatal familial insomnia (FFI). Prions are transmissible particles that are devoid of nucleic acid and seem to be composed exclusively of a modified protein (PrPSc).The normal, cellular PrP (PrPC) is converted into PrPSc through a posttranslational process during which it acquires a high β-sheet content. In fCJD, GSS, and FFI, mutations in the PrP gene located on the short arm of chromosome 20 are the cause of disease. Considerable evidence argues that the prion diseases are disorders of protein conformation.     

Conclusions of the Symposium

On the basis of twenty-one kindreds and three cases from uninformative families, the Symposium has confirmed that fatal familial insomnia (FFI) is genotypically and phenotypically distinct and, likely, the third most common inherited prion disease. The genotype, characterized by the D178N mutation on the prion protein (PrP) gene coupled with the methionine codon at position 129 has been demonstrated in all cases. The immunoblot pattern of the PrP^res associated with FFI shows a molecular mass of approximately 19kDa for the core protein and a marked underrepresentation of the unglycosylated form. The histopathology, characterized by marked thalamic and inferior olivary atrophy with a variable degree of cerebral cortical spongiosis has been observed in all but two cases. The disease duration was found to be significantly shorter in the FFI subjects homzygous at codon 129 than in the heterozygous subjects. The FFI sleep disorder is characterized by lack of spindle activity and disruption of the wake-sleep cycle which can only be established, or excluded, by polysomnography. Autonomic, endocrine and cognitive impairments also require careful assessment in each case. A condition lacking the D178N mutation and pathologically identical to FFI has been reported. Presence of sleep, autonomic and endocrine abnormalities needs to be demonstrated to identify this condition as a sporadic form of FFI. The pathophysiology of the sleep disorder, the pathogenic mechanisms, fine and early structural changes, including the role of apoptosis, and disease penetrance are the major unresolved issues in FFI.     

Regulatory sequences of the PRNP gene influence susceptibility to sporadic Creutzfeldt-Jakob disease

The prion diseases are fatal neurodegenerative disorders that afflict both humans and animals. They comprise kuru, Creutzfeldt-Jakob disease (CJD), Gerstmman-Straussler-Scheinker syndrome (GSS), and fatal familial insomnia (FFI). Both GSS, FFI and approximately 10% of CJD cases are genetically linked disorders, whereas 90% of CJD cases are not associated with mutations in the PRNP coding region, therefore other factors must be involved in pathogenesis of these forms of CJD. There is strong evidence that in transgenic mice the level of PrP gene expression influences the initiation and progression of the prion diseases. Moreover, in in vitro experiments demonstrated that mutations in the regulatory region of PRNP gene altered gene expression, therefore it may be expected that PrP expression level influences the susceptibility to CJD. In order to investigate whether single nucleotide polymorphisms within regulatory region of PRNP may modulate genetic susceptibility to sporadic CJD we examined an association of the C/G polymorphism at position -101 with the sCJD. In our study -101G polymorphism is over-represented among sCJD PRNP codon 129M/V cases compared with the control group. Our data suggest that polymorphism at position -101 in the regulatory region of PRNP may be a risk factor for sCJD among codon 129 heterozygotes.     

Fatal Familial Insomnia and Familial Creutzfeldt-Jakob Disease: Clinical, Pathological and Molecular Features

Fatal familial insomnia (FFI) and a subtype of familial Creutzfeldt-Jakob disease (CJD¹⁷⁸) are two prion diseases that have different clinical and pathological features, the same aspartic acid to asparagine mutation (D178N) at codon 178 of the prion protein (PrP) gene, but distinct genotypes generated by the methionine-valine polymorphism at codon 129 (129M or 129V) in the mutant allele of the PrP gene. The D178N, 129M allele segregates with FFI while the D178N, 129V allele segregates with CJD¹⁷⁸. The proteinase K resistant PrP (PrP^res) isoforms present in FFI and CJD¹⁷⁸ differ in degree of glycosylation and size. Thus, the amino acid, methionine or valine, at position 129 of the mutant allele, in conjunction with D178N mutation results in significant alterations of PrP^res in FFI and CJD¹⁷⁸. The 129 polymorphic site also exerts influence through the normal allele: the course of the disease is shorter in the patients homozygous at codon 129 and other minor but consistent phenotypic differences occur between homozygous and heterozygous FFI patients. The comparative study of PrP^res distribution in FFI homozygotes and heterozygotes at codon 129 has lead to the conclusion that the phenotypic differences observed between these two FFI patient populations may be the result of different rates of conversion of normal PrP into PrP^res, at least in some brain regions.     

Neuropathological Diagnostic Criteria for Creutzfeldt-Jakob Disease (CJD) and Other Human Spongiform Encephalopathies (Prion Diseases)

Neuropathological diagnostic criteria for Creutzfeldt-Jakob disease (CJD) and other human transmissible spongiform encephalopathies (prion diseases) are proposed for the following disease entities: CJD - sporadic, iatrogenic (recognised risk) or familial (same disease in 1st degree relative): spongiform encephalopathy in cerebral and/or cerebellar cortex and/or subcortical grey matter; or encephalopathy with prion protein (PrP) immuno-reactivity (plaque and/or diffuse synaptic and/or patchy/perivacuolar types). Gerstmann-Sträussler-Scheinker disease (GSS) (in family with dominantly inherited progressive ataxia and/or dementia): encephalo(myelo)pathy with multicentric PrP plaques. Familial fatal insomnia (FFI) (in member of a family with PRNP178 mutation): thalamic degeneration, variable spongiform change in cerebrum. Kuru (in the Fore population). Without PrP data, the crucial feature is the spongiform change accompanied by neuronal loss and gliosis. This spongiform change is characterised by diffuse or focally clustered small round or oval vacuoles in the neuropil of the deep cortical layers, cerebellar cortex or subcortical grey matter, which might become confluent. Spongiform change should not be confused with non-specific spon-giosis. This includes status spongiosus (“spongiform state”), comprising irregular cavities in gliotic neuropil following extensive neuronal loss (including also lesions of “burnt-out” CJD), “spongy” changes in brain oedema and metabolic encephalopathies, and artefacts such as superficial cortical, perineuronal, or perivascular vacuolation; focal changes indistinguishable from spongiform change may occur in some cases of Alzheimer's and diffuse Lewy body diseases. Very rare cases might not be diagnosed by these criteria. Then confirmation must be sought by additional techniques such as PrP immunoblotting, preparations for electron microscopic examination of scrapie associated fibrils (SAF), molecular biologic studies, or experimental transmission.     

Crouzon综合征基因突变检测

目的 研究1个Crouzon综合征家系及1例散发的Crouzon综合征患者的成纤维生长因子受体2(fibroblast growth factors receptor 2,FGFR2)基因突变情况.方法 在1个Crouzon综合征家系的10名成员,和另一例散发者的外周血提取基因组DNA,PCR扩增FGFR2基因的第8和10外显子(部分家族成员仅扩增第8外显子),产物纯化后直接进行DNA测序检测突变.结果 家系中3名成员及另1例散发者FGFR2基因第8外显子的833位核苷酸发生G→T的转换突变,该突变为错义突变,使该位点所编码的氨基酸由半胱氨酸变为苯丙氨酸(C278F).该突变为杂合子突变.结论 FGFR2基因突变是Crouzon综合征致病原因.     

Molecular Pathology of Fatal Familial Insomnia

Fatal familial insomnia (FFI) is linked to a mutation at codon 178 of the prion protein gene, coupled with the methionine codon at position 129, the site of a methionine/valine polymorphism. The D178N mutation coupled with the 129 valine codon is linked to a subtype of Creutzfeldt-Jakob disease (CJD¹⁷⁸) with a different phenotype. Two protease resistant fragments of the pathogenic PrP (PrP^res), which differ in molecular mass, are associated with FFI and CJD¹⁷⁸, respectively, suggesting that the two PrP^res have different conformations and hence they produce different disease phenotypes. FFI transmission experiments, which show that the endogenous PrP^res recovered in affected syngenic mice specifically replicates the molecular mass of the FFI PrP^res inoculated and is associated with a phenotype distinct from that of the CJD¹⁷⁸ inoculated mice, support this idea. The second distinctive feature of the FFI PrP^res is the underrepresentation of the unglycosylated PrP^resform. Cell models indicate that the underrepresentation of this PrP^res form results from the PrP dys-metabolism caused by the D178N mutation and not from the preferential conversion of the glycosylated forms. Codon 129 on the normal allele further modifies the FFI phenotype determining patient subpopulations of 129 homozygotes and heterozygotes: disease duration is generally shorter, insomnia more severe and histopathology more restricted to the thalamus in the homozygotes than in the heterozygotes The allelic origin of PrP^res fails to explain this finding since in both cases FFI PrP^res is expressed only by the mutant allele. Despite remarkable advances, many issues remain unsolved precluding full understanding of the FFI pathogenesis.     

Detection of Molecular Alterations in Medullary Thyroid Carcinoma Using Next-Generation Sequencing: an Institutional Experience

Medullary thyroid carcinoma (MTC) harbors rearranged during transfection (RET) gene and rarely RAS gene mutations. The knowledge of the type of gene mutation in MTC is important to determine the treatment of the patients and the management of their family members. Targeted next-generation sequencing with a panel of 47 genes was performed in a total of 12 cases of sporadic (9/12) and hereditary MTC (3/12). Two of three hereditary MTCs had RET/C634R mutation, while the other one harbored two RET mutations (L790F and S649L). All the sporadic MTC had RET/M918T mutation except one case with HRAS mutation. Next-generation sequencing (NGS) can provide comprehensive analysis of molecular alterations in MTC in a routine clinical setting, which facilitate the management of the patient and the family members.