Preimplantation diagnosis for early-onset Alzheimer disease caused by V717L mutation

Context  Indications for preimplantation genetic diagnosis (PGD) have recently been expanded to include disorders with genetic predisposition to allow only embryos free of predisposing genes to be preselected for transfer back to patients, with no potential for pregnancy termination. Objective  To perform PGD for early-onset Alzheimer disease (AD), determined by nearly completely penetrant autosomal dominant mutation in the amyloid precursor protein (APP) gene. Design  Analysis undertaken in 1999-2000 of DNA for the V717L mutation (valine to leucine substitution at codon 717) in the APP gene in the first and second polar bodies, obtained by sequential sampling of oocytes following in vitro fertilization, to preselect and transfer back to the patient only the embryos that resulted from mutation-free oocytes. Setting  An in vitro fertilization center in Chicago, Ill. Patients  A 30-year-old AD-asymptomatic woman with a V717L mutation that was identified by predictive testing of a family with a history of early-onset AD. Main Outcome Measures  Results of mutation analysis; pregnancy outcome. Results  Four of 15 embryos tested for maternal mutation in 2 PGD cycles, originating from V717L mutation–free oocytes, were preselected for embryo transfer, yielding a clinical pregnancy and birth of a healthy child free of predisposing gene mutation according to chorionic villus sampling and testing of the neonate's blood. Conclusion  This is the first known PGD procedure for inherited early-onset AD resulting in a clinical pregnancy and birth of a child free of inherited predisposition to early-onset AD.      

Phytosterolaemia in three unrelated South African families.

Phytosterolaemia (beta-sitosterolaemia), a rare, autosomal recessive disorder, has not hitherto been reported in Southern Africa. We report four new homozygous patients, from three unrelated families with significant beta-sitosterolaemia (6.6-11.3%), campesterolaemia (2.2-4.6%) and clearly detectable, though unquantified, levels of cholestanol. Three of the four patients had characteristic cutaneous and tendinous xanthomas within the first decade of life. The fourth patient, a 5 year old, was free of xanthomas despite persistently elevated concentrations of plant sterols in her plasma. All our patients were female bringing the male:female ratio in reported cases to 8:23. All were at or below the 50th percentile for height and weight, and presented at some stage with borderline, hypochromic anaemia associated with red cell abnormalities and thrombocytopaenia. The oldest patient showed suggestive clinical evidence of atherosclerosis affecting her aorta, ileofemoral bifurcation and possibly coronary arteries. All homozygotes responded to a diet restricted in phytosterols and the administration of cholestyramine with falls in plasma sterols of up to 68%. The recent discovery of a possible inherited defect in the synthesis of HMG CoA reductase in patients with phytosterolaemia makes this disorder a model system for studying the biological role of this enzyme in regulating the absorption and clearance of sterols other than cholesterol, and the factors governing the sterol composition of cell membranes.     

两个家系中X连锁视网膜色素变性的RP2 基因无义突变

目的 检测引起2个家系产生X连锁视网膜色素变性的RP2基因突变。方法 根据RP2基因外显子的内含子DNA序列合成8对引物，以人基因组DNA为模板，PCR扩增出包含RP2基因所有外显子的8个片段。扩增产物化后直接测序。通过比较病人和正常人相应的DNA序列，检测基因突变位点。结果 在2个家系中首次检测到RP2基因的同一个无义突变38C→T。突变位于RP2基因的第2外显子。它使该基因编码精氨酸的遗传密码CGA变为终止密码TGA，引起发病。结论 该突变的检出有助于RP2蛋白的功能分析和X连锁视网膜色素变性的基因诊断。     

A novel MFN2 mutation causing Charcot-Marie-Tooth type 2A disease in a Chinese family

No abstract is required for case report     

11例慢性家族性良性天疱疮患者的基因突变

目的：对11例中国慢性家族性良性天疱疮(Hailey—Hailey disease．HHD)患者进行基因突变研究。方法：根据病史、临床表现和组织病理诊断慢性家族性良性天疱疮，收集家系资料，提取外周血DNA，设计引物，采用聚合酶链反应、DNA直接测序、克隆测序等方法对11例非同家族的慢性家族性良性天疱疮患者ATP2C1基因进行突变检测：结果：11例患者中，发现3例提前终止突变，发现2例剪切位点突变：其中有4例的突变方式尚未见报道。结论：提前终止突变和剪切位点突变会影响转录和翻译的结果，推断本实验所检测出的突变是造成相应家系临床病变的特异突变。     

常染色体隐性遗传早发型帕金森病家系的DJ-1基因研究

目的：探讨DJ-1基因与中国人常染色体隐性遗传早发型帕金森病（AREP）家系的关系.方法：对3个AREP家系的6位患者和23位成员进行系统的临床检查并进行DJ-1基因PCR扩增,标本进行基因测序.结果：所有研究对象的DJ-1基因外显子均扩增成功.3个家系中6位患者的DJ-1基因所有外显子测序均未发现突变.结论：DJ-1基因突变在中国人AREP家系中发生率较低,不是常见致病因素.     

应用实时荧光定量PCR技术检测常染色体 隐性遗传性早发型帕金森综合征的 DJ 1基因外显子重排突变

目的：建立应用实时荧光定量PCR技术（real time polymerase chain reaction,real time PCR）检测DJ 1基因外显子重排突变的技术平台,并应用该技术对常染色体隐性遗传性早发型帕金森综合征（autosomal recessive early onset Parkinsonism, AREP）DJ 1基因进行外显子重排突变分析。方法：应用实时荧光定量PCR分析方法,对22个AREP家系先证者和30个正常对照的DJ 1基因进行外显子重排突变分析。结果：本研究中获得了扩增效率和特异性均满意的DJ 1基因各编码外显子实时荧光定量PCR反应条件及各外显子引物;本组AREP患者未发现DJ 1基因的外显子重排突变。结论：建立了应用实时荧光定量PCR技术进行DJ 1基因外显子重排突变检测的技术平台;中国人群AREP患者DJ 1基因外显子重排突变可能罕见。     

A novel mutation in ornithine transcarbamylase gene causing mild intermittent hyperammonemia

We report a 3-year-old Saudi boy with recurrent episodes of vomiting, poor feeding, and altered mental status accompanied by an intermittent mild hyperammonemia, and a large elevation of urinary orotic acid. Sanger sequencing of the ornithine transcarbamylase (OTC) gene revealed a novel hemizygous deletion at the fourth nucleotide of intron 4 (c.386+4delT) in the proband and his asymptomatic mother. This novel mutation in the OTC gene is responsible for the late-onset phenotype of OTC deficiency.Hyperammonemia is a life-threatening condition caused by inherited and acquired diseases. Urea cycle disorders (UCD) are the leading inborn errors that present with hyperammonemia.1 All the 6 urea cycle enzyme defects are inherited as autosomal recessive except ornithine transcarbamylase (OTC) deficiency (OTCD; MIM#311250), which is an X-linked disease.2 Ornithine transcarbamylase is a mitochondrial enzyme that catalyzes the second step of the urea cycle leading to the synthesis of citrulline from ornithine and carbamoyl phosphate.1 The prevalence of OTC deficiency is estimated to range from 1 in 40,000 to 1 in 80,000.3,4 The phenotype of OTC deficiency is extremely heterogeneous. Patients with OTC deficiency usually present with poor feeding, vomiting, and respiratory alkalosis, and may progress to seizures, encephalopathy, and death.1 Late-onset disease presents beyond the neonatal period with life-threatening hyperammonemia and occasionally with intermittent episodes of metabolic decompensation.5 These patients with late-onset disease usually have more residual enzyme activity compared to classic OTC phenotype. Aside from the clinical phenotype, the diagnosis of OTC deficiency is based on the presence of hyperammonemia, high glutamine, and low arginine in serum amino acid and demonstration of orotic aciduria.2 Previously, enzyme study using liver biopsy tissues was the gold standard for the diagnosis of this condition.1 Currently, the diagnosis is confirmed by detection of the pathogenic mutation(s) in the OTC gene. The human OTC gene was mapped to the short arm of chromosome Xp21.1 and encodes a 354 amino acids protein.2 There exists mutational heterogeneity in the OTC gene. More than 341 mutations have been identified in the OTC gene that are distributed throughout the gene and most of which are private mutations.5 A large number of reported variants are missense mutations (68%), followed by nonsense, insertions, and deletions in the coding region (18%). The remaining variants include splice site variants affecting splicing of OTC mRNA.5,6 In this study, we report a novel mutation in the OTC gene in a Saudi boy who presented with mild intermittent hyperammonemia.     

19例喀什地区维吾尔族居民的主动脉疾病基因突变分析

目的 探讨喀什地区少数民族的主动脉疾病基因突变类型,分析其与临床表型的相关性。方法 利用二代测序技术对包含马凡综合征在内的19例新疆维吾尔族主动脉疾病家系的37个相关致病基因进行基因检测|、分析,并对其近亲家属完成sanger验证。结果 本研究纳入19个主动脉疾病家系,共检测出23个突变位点,有11例先证者（57.89%）存在一个或以上的基因突变。其中有1例（5.26%）为明确的致病性突变;8例（42.11%）检测出意义未明性突变;7例（36.84%）检测出良性/可能良性突变。23个突变位点中包括有1个（5.26%）明确的致病性突变位点,14个（60.87%）意义未明的基因突变,8个（34.78%）良性/可能良性突变。对14个意义未明突变位点采用SIFT及Polyphen2 HDIV软件预测,发现6个（42.86%）为有害性/可能有害性 突变。对8个良性/可能良性突变位点进行上述软件预测,结果均为有害性/可能有害性突变。结论 本研究发现了23个突变位点,其中22个尚待以后更多的患者数据进行验证。基因诊断有助于患者及其近亲属的早期诊断及鉴别诊断。     

HLA-DRB1 genes in 5 rheumatic disease multi-case families

OBJECTIVE: To detect HLA-DRB1 (DR1-10) alleles in 5 families with multi-case rheumatic diseases, and to study the possible influence of DRB1 genes in the pathogenesis of rheumatic diseases. METHODS: Sequence-Specific Primer PCR (PCR-SSP) method was used to examine HLA-DRB1 alleles. Totally 36 members of 5 families and 166 healthy people were involved in this study. The results were assessed by Chi-square test. RESULTS: The HLA-DRB1 allele frequency in the patients and their relatives was similar. No significant difference was found. But DR4 allele frequency in the patients (90.9%) and their relatives (68%) was much higher than that in normal controls (16.8%) and the difference was statistically significant (P < 0.0001). In family 4, two RA patients have different DRB1 alleles, while in family 5, two patients have the same DRB1 alleles, one developed SLE and the other developed RA. CONCLUSIONS: DR4 is closely related to rheumatoid arthritis. The nelatives of RA patients may be at greater risk to develop RA than individuals without family history. Some patients had the same DRB1 allele but developed different rheumatic diseases. This suggested that there might be some common pathways in genetic predisposing of rheumatic diseases. On the other hand, only a few patients with the same DRB1 allele developed rheumatic diseases during their life, so other factors besides DRB1 gene might also be involved in the pathogenesis of rheumatic diseases.     

阿尔茨海默病患者语义记忆损害的研究

目的:分析阿尔茨海默病患者听觉字词理解障碍的特点,探讨其语义记忆损害的机制。方法:采用词画匹配的方法,比较10例阿尔茨海默病患者在呈现时间、语义相关性、字词频率、反应一致性4种条件下的听觉字词理解的成绩。结果:字词频率是决定阿尔茨海默病患者成绩的一个主要因素,没有观察到呈现时间、语义相关性作用和反应不一致性。结论:阿尔茨海默病患者的语义记忆损害系由于已存贮的语义表象本身缺陷所致。     

Genotype-phenotype analysis in early-onset Alzheimer's disease due to presenilin-1 mutations at codon 139

Mutations in the presenilin-1 (PS-1) gene are the main cause of autosomal-dominant early onset Alzheimer's disease (EOAD) and show a high penetrance of symptoms. There are more than 100 mutations in the PS-1 gene. Among them are at present four different missense mutations known at position 139 on exon 5. Lack of genotyping in other family members may lead to the suggestion of sporadic cases. We present the case of a 46-year old German female with EOAD. Cognitive decline started at the age of 32, while myoclonic and tonic-clonic jerks occurred later. Disease symptoms were present in three generations of her family. Genetic analysis revealed the M139V mutation on exon 5 of the PS-1 gene. We compared the clinical data of this family with seven previously reported families and two sporadic cases with mutations at the codon 139. The genotype-phenotype analysis showed marked intrafamilial homogeneity, but interfamilial heterogeneity in relation to the onset, duration, and progression of the disease. Onset and duration were not correlated to the amino acid exchanged. Another modifying genetic or environmental factor is probable.     

A founder mutation of the MSH2 gene and hereditary nonpolyposis colorectal cancer in the United States

Context  Hereditary nonpolyposis colorectal cancer (HNPCC), also known as Lynch syndrome, is caused by mutations in the mismatch repair genes and confers an extraordinarily high risk of colorectal, endometrial, and other cancers. However, while carriers of these mutations should be identified, counseled, and offered clinical surveillance, at present the mutations are not tested for in mutation analyses. Objective  To describe the prevalence of a large genomic deletion encompassing exons 1 to 6 of the MSH2 gene that is widespread in the US population as a result of a founder effect. Design, Setting, and Patients  Ongoing genealogical and historical study conducted to assess the origin and spread of an MSH2 mutation previously identified in 9 apparently unrelated families with putative HNPCC and living in widely different geographic locations in the United States. Main Outcome Measures  Classification of family members as carriers or noncarriers of the MSH2 mutation; spread of the mutation across the continental United States. Results  To date, 566 family members of the 9 probands have been identified to be at risk and counseled; 137 of these have been tested, and 61 carry the founder mutation. Three families have been genealogically shown to descend from a German immigrant family that arrived and first settled in Pennsylvania in the early 1700s. Movements of branches of the family from Pennsylvania through North Carolina, Alabama, Kentucky, Missouri, Iowa, Nebraska, Utah, Texas, and California have been documented, and carriers of the mutation have already been diagnosed in 14 states. In contrast, the deletion was not found among 407 European and Australian families with HNPCC. Conclusion  The postulated high frequency and continent-wide geographic distribution of a cancer-predisposing founder mutation of the MSH2 gene in a large, outbred (as opposed to genetically isolated) population, and the ease with which the mutation can be detected, suggest that the routine testing of individuals at risk for HNPCC in the United States should include an assay for this mutation until more is learned about its occurrence.      

Canadian patient played key role in uncovering secrets about early-onset Alzheimer's disease.

Last June, the University of Toronto announced that Canadian scientists and a team of international researchers had discovered the gene responsible for most cases of early-onset Alzheimer's disease. One of the key players in that discovery had died just 3 months earlier. Frances Hodge, who participated in a battery of tests for the 20 years she lived with the disease, helped lead researchers to gene S182--and an ember of hope for future generations.     

SORL1基因敲除小鼠可作为散发性阿尔茨海默病模型

目的通过与正常小鼠、淀粉样前体蛋白（APP）/PSE1双转基因小鼠行为学和病理学的比较,证明SORL1敲除小鼠可作为 1 种散发性阿尔茨海默病模型。方法Crispr/Case9 技术对小鼠受精卵SORL1 基因进行编辑,通过检测小鼠DNA序列和 Western blot检测SORL1等方法筛选和鉴定SORL1-/-小鼠。实验分为对照组、SORL1-/-组、APP/PSE1组。Morris水迷宫检测小 鼠的学习记忆能力、免疫组化和Western blot分别检测小鼠脑组织中APP、β淀粉样蛋白的表达。结果SORL1-/-小鼠的DNA测 序结果是两条染色体SORL1基因CAAT碱基缺失,而正常小鼠SORL1基因无CAAT碱基的缺失;Western blot检测SORL1-/-组 小鼠脑组织无SOLR1表达。在Morris水迷宫的定位航行实验中,与对照组比较,SORL1-/-组和APP/PSE1组小鼠平均逃避潜伏 期均明显延长（P<0.05）,SORL1-/-组和APP/PSE1组比较,小鼠的平均逃避潜伏期差异无统计学意义（P>0.05）;在Morris水迷宫 的空间探索实验中,与对照组比较,SORL1-/-组和APP/PSE1组小鼠平均穿越平台次数均减少（P<0.05）,SORL1-/-组和APP/PSE1 组比较,小鼠平均穿越平台次数差异无统计学意义（P>0.05）。免疫组化和Western blot检测结果均显示SORL1-/-组小鼠脑组织 中APP和Aβ表达明显较对照组多,SORL1-/-组与APP/PSE1 组脑组织的APP和β淀粉样蛋白表达差异无统计学意义。结论 SORL1-/-小鼠可出现APP/PSE1小鼠相似的行为学和病理学的改变,可作为一种散发性阿尔茨海默病模型。     

A novel point mutation in CD18 causing leukocyte adhesion deficiency in a Chinese patient

Background Leukocyte adhesion deficiency type 1 （LAD-l） is a rare, autosomal recessive inherited immunodeficiency disease characterized by recurrent severe bacterial infection, impaired pus formation, poor wound healing, associated with the mutation in the CD18 gene responsible for the ability of the leucocytes to migrate from the blood stream towards the site of inflammation. Correct and early diagnosis of LAD-1 is vital to the success of treatment and prevention of aggressive infections. The purpose of this study was to collect the clinical findings of the disease and to identify the genetic entity. Methods CD18 expression in the peripheral blood leukocytes from the patient, his parents and normal control was measured with flow cytometry. The entire coding regions of the CD18 gene were screened with direct sequencing genomic DNA. Results CD18 expression level on this patient＇s leukocyte surface was significantly decreased, with normal level in control group, his father and mother. Gene analysis revealed that this patient had a homozygous c.899A〉T missense mutation in exon 8 of CD18 gene, causing the substitution of Asp to Val at the 300 amino acid. His parents were both heterozygous carriers while no such mutation was found in 50 normal controls. Conclusion This study disclosed a novel point mutation Asp 300 Val located in a highly conserved region （HCR） of CD18 and confirmed the heterogeneity of the mutations causing LAD-1, indicating it was quite beneficial to establish correct and early diagnosis in children with severe LAD-1.     

A novel SMPD1 mutation in two Chinese sibling patients with type B Niemann-Pick disease

Type B Niemann-Pick disease is an autosomal recessive sphingolipidosis due to mutations in the sphingomyelin phosphodiesterase 1 gene (SMPD1). Here we present molecular findings for two sibling patients. One mutation V36A due to c.107T>C in exon 1 is a single nucleotide polymorphism and the other N522S due to c.1565 A>G in exon 6 is a novel missense mutation. This non-fatal missense mutation leads to –20% residual lysosomal acid sphingomyelinase activity in vitro and only results in hepatosplenomegaly without neurologic involvement.

     

脑灵汤对阿尔茨海默病模型大鼠TGF-β1表达的影响

目的 探讨脑灵汤对阿尔茨海默病(AD)模型大鼠TGF-β1(转化生长因子β1)表达的影响.方法 采用向大鼠海马内注射Aβ1-42(β淀粉样蛋白)建立AD模型,通过Y-电迷宫实验检测各组大鼠学习记忆能力;行HE染色观察海马CA3区神经元形态;采用刚果红染色检测Aβ的沉积;用免疫组化SP法检测TGF-β1的表达情况.结果 脑灵汤能改善模型大鼠的学习记忆能力,减少Aβ的沉积,且脑灵汤组TGF-β1的表达较AD模型大鼠的表达增加,差异有统计学意义(P<0.05).HE染色结果,脑灵汤组大鼠海马CA3区细胞排列较整齐、均匀,结构较清晰,形态、排列、数目较模型组明显改善;刚果红染色结果,正常组、假手术组大鼠脑组织切片中未见A13沉积;模型组大鼠脑组织切片在CA1区与齿状回之问可见明显Aβ1沉积;脑灵汤组未发现明显的Aβ沉积.结论 脑灵汤能增强AD大鼠海马区域TGF-β1的表达,可能通过此机制减少海马AB蛋白的沉积,从而改善模型大鼠学习记忆能力.     

ApoA1基因启动子区域多态性与冠心病关联研究

研究A基因启动子突变频率。方法用EB染色PCR－SSCP法分析ApoA1基因上游270bp范围的基因突变。结果唐山正常人Apol有4种基因型，其频率为Ⅰ型0.84，Ⅱ型0.12，Ⅲ型0．02，Ⅳ型0.02；冠心病患者发现5种基因型：Ⅰ型0．765，Ⅱ型0.1176，Ⅲ型0．029，Ⅳ型0．059，Ⅴ型0．029。结论基因突变频率两组间无明显差别，基因突变与ApoA1水平有明显关系，与ApoB100TGTCHDL－C无明显关系。