A novel mitochondrial tRNA gene mutation in a chinese family with dilated cardiomyopathy and sensorineural deafness

Objective： To determine whether a mutation of mitochondrial DNA induces familial dilated cardiomyopathy in Chinese families with cardiomyopathy, and analyzed the correlation between the genotype and phenotype. Methods： Affected members in three Chinese families of the familial dilated cardiomyopathy underwent clinical evaluation and DNA analysis. Polymerase chain reaction and direct DNA sequencing were used to screen for mitochondrial DNA mutation. The type of mtDNA variations and clinical situation were analysed on the patients with mitochondrial DNA mutation. Results： The mitochondrial A3434G mutation was identified in one of the three families,the 3434 th nucleotide A was replaced by G, which led to change of amino acid. No mutations were identified in the clinically unaffected members of the family and all members of the other two families. Conclusion： This study indicates that the mitochondrial A3434G mutation maybe related with familial dilated cardiomyopathy and deafness.     

China aims for national chain of anti-smoking clinics

Background Familial pulmonary arterial hypertension （FPAH） is an autosomal dominant disorder characterized by plexiform lesions of endothelial cells in pulmonary arterioles which leads to elevated pulmonary arterial pressure, right-sided heart failure and death. Heterozygous mutations in the bone morphogenetic protein type II receptor gene （BMPR2） have been found to underlie a majority of FPAH cases. More than 140 distinct mutations have been identified in FPAH cases and in idiopathic pulmonary arterial hypertension （IPAH） cases, but only one mutation has been reported in Chinese patients. Methods A three-generation pedigree of FPAH and another 10 patients with IPAH were collected. In the family, two of the 9 surviving and one deceased family member were diagnosed as FPAH. The entire protein-coding region and intron/exon boundaries of the BMPR2 gene were amplified by PCR using DNA samples from affected individuals. Direct sequencing of PCR products was performed on both the sense and antisense strands. To confirm the segregation of the mutation within the family and exclude the presence of the mutation in normal subjects, the relevant exon was amplified by PCR, followed by mutation-specific RPLP analysis. Results In the Chinese pedigree with FPAH an A-to-T transition at position 1157 in exon 9 of the BMPR2 gene was identified which resulted in a Glu386Val mutation. We confirmed the segregation of the mutation within the family and excluded the presence of the mutation in a panel of 200 chromosomes from normal subjects. No mutation was detected in BMPR2 in the other 10 patients with IPAH. Conclusions This amino acid substitution occurs at a glutamic acid that is highly conserved in all type Ⅱ TGF-β receptors. The nearly invariant Glu forms an ion pair with an invariant Arg at position 491 thereby helping to stabilize the large lobe. Substitution of Arg at position 491 is the most frequently observed missense mutation in FPAH, but until now no mutations at position 386 have been found in FPAH. The pr     

R25G mutation in exon 1 of LMNA gene is associated with dilated cardiomyopathy and limb-girdle muscular dystrophy 1B

Background Mutations of the LMNA gene encoding lamin A and C are associated with dilated cardiomyopathy （DCM）, conduction system defects and skeletal muscle dystrophy. Here we report a family with a mutation of the LMNA gene to identify the relationship between genotype and phenotype. Methods All 30 members of the family underwent clinical and genetic evaluation. A mutation analysis of the LMNA gene was performed. All of the 12 exons of LMNA gene were extended with polymerase chain reaction （PCR） and the PCR products were screened for gene mutation by direct sequencing. Results Ten members of the family had limb-girdle muscular dystrophy （LGMD） and 6 are still alive. Two patients suffered from DCM. Cardiac arrhythmias included atrioventricular block and atrial fibrillation; sudden death occurred in 2 patients. The pattern of inheritance was autosomal dominant. Mutation c.73C〉G （R25G） in exon 1 encoding the globular domains was confirmed in all of the affected members, resulting in the conversion of arginine （Arg） to glycine （Gly）. Conclusions The mutation R25G in exon 1 of LMNA gene we reported here in a Chinese family had a phenotype of malignant arrhythmia and mild LGMD, suggesting that patients with familial DCM, conduction system defects and skeletal muscle dystrophy should be screened by genetic testing for the LMNA gene.     

一个中国Gilbert综合征家系的临床和遗传学特征分析

Objective To perform clinical and genetic pedigree analyses of a Chinese male patient with Gilbert's syndrome and his relatives. Methods Blood sample were collected from the proband and his relatives by liver function test, etiological examination and genetic analysis to exclude other related diseases. The phenobarbital-responsive enhancer module (PBREM) , TATA box and common mutation sites in exons of UGT1A1 gene were amplified by polymerase chain reaction (PCR) and the products screened by direct DNA sequencing. Results c. -3279T ＞ G in PBREM, TA insertion in TATA box and Gly71Arg were observed in this family. A linkage disequilibrium is also noted between c. -3279T ＞ G and TA insertion. In four affected members, three are heterozygotes and one is homozygote. The correlation between genotype and phenotype with a high serum level of unconjugated bilirubin was confirmed. Conclusion c. -3279T ＞ G in PBREM, TA insertion in TATA box and Gly71 Arg are essential for the pathogenesis of Gilbert's syndrome in this Chinese family. Gilbert's syndrome in this family is inherited in an autosomal recessive manner.     

一个中国Gilbert综合征家系的临床和遗传学特征分析

Objective To perform clinical and genetic pedigree analyses of a Chinese male patient with Gilbert's syndrome and his relatives. Methods Blood sample were collected from the proband and his relatives by liver function test, etiological examination and genetic analysis to exclude other related diseases. The phenobarbital-responsive enhancer module (PBREM) , TATA box and common mutation sites in exons of UGT1A1 gene were amplified by polymerase chain reaction (PCR) and the products screened by direct DNA sequencing. Results c. -3279T ＞ G in PBREM, TA insertion in TATA box and Gly71Arg were observed in this family. A linkage disequilibrium is also noted between c. -3279T ＞ G and TA insertion. In four affected members, three are heterozygotes and one is homozygote. The correlation between genotype and phenotype with a high serum level of unconjugated bilirubin was confirmed. Conclusion c. -3279T ＞ G in PBREM, TA insertion in TATA box and Gly71 Arg are essential for the pathogenesis of Gilbert's syndrome in this Chinese family. Gilbert's syndrome in this family is inherited in an autosomal recessive manner.     

Atrial natriuretic peptide gene polymorphism is not associated with hypertrophic cardiomyopathy

Background Hypertrophic cardiomyopathy （HCM） is a primary autosomal dominant inheritant myocardial disease with heterogeneity in clinical manifestations, natural history and prognosis. Even carrying an identical gene mutation among family members, a va[iety of clinical phenotypes have been found in patients with HCM. Modifier genes may contribute to the diversity. The plasma levels of atrial natriuretic peptides （ANP） were found previously to be elevated in HCM. Our studies suggested that ANP gene promoter polymorphism is associated with left ventricular hypertrophy in hypertension. The present study aimed to determine whether the two SNPs in the ANP gene are associated with HCM Methods We determined the relationships between the ANP gene polymorphism and HCM in 262 HCM patients and 614 age- and sex-matched healthy individuals. All of the subjects were genotyped for -A2843G and A188G polymorphisms. Results The genotype frequency in the -A2843G and A188G polymorphisms of the ANP gene was not significantly different between the HCM patients and controls. The -A2843G and A188G polymorphisms were also not associated with clinical phenotype in cardiomyopathy patients. Conclusions The polymorphisms of the ANP gene are not associated with increasing risk of HCM or clinical phenotypes. The variations of the ANP gene may not serve as a genetic modifier for the development of HCM.     

A novel KIAA0196 (SPG8) mutation in a Chinese family with spastic paraplegiaGenetic analysis results

Abstract Background: Hereditary spastic paraplegia is one of the most heterogeneous genetic neurodegenerative diseases, caused by mutations in more than 50 different genes. The eighth HSP locus, SPG8, is on chromosome 8p24.13.SPG8 is a rare autosomal dominant hereditary spastic paraplegia (AD-HSP) caused by mutations in the KIAA0196 gene, with only seven SPG8 families described to date. Methods: The KIAA0196 gene was sequenced and clinical data were analyzed in a Chinese non-consanguineous family with typical clinical features of SPG8. The proband was examined with brain and spinal magnetic resonance image (MRI). Results: Based on clinical criteria, pure spastic paraplegia was diagnosed in the proband and 5 other family members (5 women, 1 male), with a mean age at onset of 26.80 ± 11.30 years (range 17–43 years). The spinal cord MRI of the proband showed atrophy of the spinal cord. A novel mutation in the KIAA0196 gene (c.1771T>C; p.Ser591Pro) was identified in the family. The mutation has not been documented previously and was not detected among 100 healthy controls. Conclusion: The novel mutation is the fifth pathogenic KIAA0196 mutation to be reported. This is the first Chinese family to be reported with SPG8.     

Bilateral Pheochromocytoma as First Presentation of von HippeI-Lindau Disease in a Chinese Family

Objective To investigate the clinical and genetic features of a Chinese family with yon Hippel- Lindau （VHL） disease revealed by bilateral pheochromocytoma. Methods The proband and other members in a Chinese family with familial pheochromocytoma were clinically evaluated and followed up. Genomic DNA extracted from the peripheral blood of 8 family members （including 3 patients） was amplified by polymerase chain reaction （PCR） and the PCR products were directly sequenced. Results The first presentation in the proband, his mother, and his sister was bilateral pheochromocytoma, and the missense mutation of 695G-A （Arg161Gln） in exon 3 of VHL gene was detected in the three patients. In the follow-up study, the proband and his mother were found to have other VHL tumors, induding retinal and cerebellar hemangioblastomas and pancreatic tumor. Neither clinical presentation of VHL disease nor gene mutation was found in other family members. Conclusion VHL disease should be suspected in some patients with familial pheochromocytoma, and VHL gene screening helps to achieve early diagnosis of the disease.     

China, Japan sign agreement to share marrow donation information

Background Familial hypercholesterolemia (FH) is a type of dominant autosomal disease that causes high levels of plasma low-density lipoprotein cholesterol (LDL-C). In the past years, molecular data related to FH were limited in China. Now, to gain more information about FH, we analyzed one proband with a severe FH phenotype as well as his relatives. Methods After the entire coding sequence and the intron-exon junctions of the low-density lipoprotein receptor (LDLR) gene were amplified using PCR, we sequenced the LDLR gene of a Chinese FH family. RT-PCR was used to detect changes in the mRNA.Results Two novel mutations were identified in the LDLR gene of this family. One, W165X, was a G>A substitution at the third nucleotide of codon 165. The other, IVS5–1G>A, was also a G>A substitution at the acceptor splice site of intron 5. The most striking discovery is that the proband was heterozygous for W165X but homozygous for IVS5–1G>A. The cDNA sequencing showed that the IVS5–1G>A mutation caused the insertion of 10 nucleotides, namely GCTCTCACAA, between exon 5 and exon 6. Conclusions The two nucleotide variations are thought to be the FH-causing mutations because the co-segregation of the mutant allele with the phenotype of FH has been shown in this Chinese family. These data show an increase in the mutational spectrum of FH in China and verify a scarce mutational form in the LDLR gene.     

STUDY OF BRCAI GENE IN HEREDITARY BREAST AND OVARIAN CANCER

Objective. To investigate the BRCA1 gene in hereditary breast and ovarian cancer, early-onset breast cancer and sporadic ovarian cancer. Methods. The exons of 2, 11 and 20 of BRCA1 gene were analyzed, Polyrnerase chain reaction-single strand conformation analysia(PCR-SSCP) and PCR SSCP combined by restriction enzymes were used to screen for mutations. Mutations were further indentifed by sequencing. The loss of heterozygosity (LOH) were also investigated at the BRCA1 genetic loci D17S855 in 10 hereditary ovarian cancer. Results. A insertion mutation was detected in H7. “C“ was inserted ay nucleotide 797. It would result in truncation of the BRCA1 protein at cndon 277. A missen mutation was detected in an early-onset breast cancer(diagnosed at age 24). At nueleotide position 3732, the substitution of a “G“ to a “C“ in codon 1205 changes a Gly to a Arg. A missen mutation were also detected in three sporadic ovarian cancers. At nu-cleotide position 2051, the substitution of a “T“ to a “G“ in cndon 644 changes a Cys to a Trp. H3 and H7 patients show LOH. Conclusions. BRCA1 gene has an important effect in Chinese hereditary breast and ovarian cancer, its effect on early-onset breast cancer and sporadic ovarian cancer are still to be studied. BRCA1 gene is a tu-mor -suppressor gene.     

安徽地区汉族人家族性与散发性肥厚型心肌病MYH7基因18及20号外显子突变分析

目的分析安徽地区汉族家族性及散发性肥厚型心肌病(HCM)患者的致病基因β肌球蛋白重链(MYH7)突变位点的异同。方法对3个家系中8例HCM患者及20例散发的HCM患者进行MYH7基因18及20号外显子扫描,双脱氧末端终止法测序。结果3个家族性HCM(FHCM)家系8例患者中,有2例患者发现MYH7基因20号及18号外显子发生突变,分别为20号外显子发生Arg723Gly突变;18号外显子发生Arg663His突变;散发的20例HCM患者中,有1例发现MYH7的20号外显子上发生Ile736Thr突变,未发现18号外显子发生突变。结论MYH7基因中18号、20号外显子突变可能是安徽地区FHCM的常见突变位点之一;散发性HCM(SHCM)可能与FHCM具有相似的发病机制,但与FHCM相比,在MYH7基因中突变率较低。     

中国汉族家族性肥厚型心肌病肌球蛋白重链基因G823E突变分析

目的 研究中国人家族性肥厚型心肌病(HCM)的致病基因突变位点,分析基因型与临床表型的相互关系.方法 在1个中国汉族HCM家系中进行心脏肌钙蛋白T基因(TNNT2)、心脏肌球蛋白结合蛋白C基因(MYBPC3)和心脏β-肌球蛋白重链基因(MYH7)的突变筛查,聚合酶链反应(PCR)扩增基因功能区外显子片段,并对PCR产物进行测序分析.以120名正常志愿者为对照组.结果 在该家系接受调查的12名成员中有4名成员携带MYH7基因G823E杂合突变,该突变位点位于MYH7基因的22号外显子并使823位的甘氨酸(G)转换为谷氨酸(E),该突变在西方人中未见报道,其导致的临床表型在家系内部呈现较明显的异质性,携带该突变的家族成员发病年龄和临床症状差异较大.该家系成员TNNT2及MYBPC3基因未发现突变且对照组相同位置未发现异常.结论 MYH7基因为我国家族性HCM的致病基因之一,G823E突变所致肥厚型心肌病呈现明显的个体异质性表型.     

家族性与散发性肥厚型心肌病基因突变的对比研究

目的 研究中国家族性及散发性肥厚型心肌病（HCM）患者的致病基因突变位点的异同。方法 对10个家系中36例HCM患者及50例散发的HCM患者进行B肌球蛋白重链（MYH7）、肌钙蛋白T（TNNT2）及肌球结合蛋白C（MYBPC3）扫描,聚合酶链式反应扩增,双脱氧末端终止法测序。结果家族性HCM患者中,3个家系的13例HCM患者发现MYH7错义突变,分别为18号外显子发生G12601A突变（Arg663His）、23号外显子发生G15373A突变（Glu924Lys）、20号外显子发生T13659C突变（Ile736Thr）,散发的50例HCM患者中,有1例发现MYH7的20号外显子上T13659C突变。所有HCM患者均未发现TNNT2基因突变。家族性HCM患者中有2个家系共4例发现MYBPC3基因突变：2例为18号外显子上的Arg502Trp、2例为13号外显子碱基插入突变,即在7425～7426间插入CGGCA,导致Arg346fs移码突变;50例散发性HCM患者中未发现此基因突变。结论 MYH7和MYBPC3可能为我国家族性HCM的主要致病基因之一,而我国散发性HCM患者MYH7和MYBPC3基因突变率低;TNNT2可能不是我国HCM患者的主要致病基因。     

心脏型肌钙蛋白T基因14035c＞t突变导致家族性肥厚型心肌病的临床表型分析

目的研究中国人肥厚型心肌病（HCM）致病基因,分析基因型与临床表型的关系。方法在一个HCM家系中进行心脏型肌钙蛋白T基因（TNNT2）、心脏型肌球蛋白结合蛋白C基因（MYBPC3）和β-肌球蛋白重链基因（MYH7）突变筛查,利用聚合酶链反应（PCa）扩增其功能区的外显子片段,双脱氧末段终止法测序。家系调查资料包括临床表现、体格检查、心脏超声和心电图。结果在该家系接受家系调查的10例对象中4例携带TNNT2 14035c〉t（R130C）突变,全部于40岁之前发病,外显率100％。正常对照组同一位置未见异常,该突变位点使TNNT2基因第10号外显子130位的精氨酸变为半胱氨酸,先证者及其两兄长皆以心功能不全表现为主,先证者的两位兄长在我们随访过程中发生猝死。MYH7及MYBPC3基因未发现突变。结论TNNT2基因14035c〉t突变是该HCM家系的致病突变。其携带者的临床表型较恶。对于临床表型较恶,猝死发生率较高HCM家系有必要进行TNNT2的突变筛查。     

汉族家族性肥厚型心肌病患者的MYH7基因R663H、E924K突变

目的研究中国人家族性肥厚型心肌病(HCM)的致病基因突变位点,分析基因型与临床表型的相互关系。方法对5个家族性HCM的先证者进行β-肌球蛋白重链基因(β-MHC)扫描,聚合酶链反应(PCR)扩增其功能区外显子片段,双脱氧末端终止法测序。对阳性测序结果者进行家系中其他成员筛查,并分析患者临床表型特点。结果在其中2个家系中分别发现R663H、E924K杂合突变,而正常对照组同一位置未见异常,E924K在我国HCM患者中首次发现。结论β-MHC为我国家族性HCM的致病基因之一。其临床表型的异质性提示多因素参与了HCM的发生及外显。     

首次发现肥厚型心肌病肌球蛋白结合蛋白C基因Arg856fs突变

目的： 研究中国人群肥厚型心肌病(HCM)患者的致病基因突变位点，并对基因型与临床表型之间的关系进行分析。方法: 对76例HCM先证者进行聚合酶链反应(PCR)扩增心肌肌球蛋白结合蛋白C基因（MYBPC3）第15 16,18,26,28,34号外显子，产物做单链构象多态性(SSCP)分析，出现异常条带者将其目的片段和正常对照组该片段送检测序。结果: 在1例52岁男性患者的MYBPC3基因第26号外显子上发现了一个新的移码突变位点Arg856fs。由于在100名正常对照组中未见异常，故我们认为此突变位点为该患者的致病基因位点。结论: MYBPC3基因是我国HCM的致病基因之一。     

肥厚型心肌病心肌β-肌球蛋白重链基因Gln893Lys突变

目的：研究中国人肥厚型心肌病致病基因-β-肌球蛋白重链基因（β-MHC）,分析基因型与临床表型的关系．方法：在96例肥厚型心肌病患者及100例正常对照中进行β-肌球蛋白重链（β—MHC）基因扫描,聚合酶链反应（PCR）扩增其功能区的外显子片段,双脱氧末端终止法测序．对阳性结果者进行家系调查,收集临床资料,分析其临床表型．结果：在4个家系及2例散发患者中,β—MHC基因第23号外显子的Gln893Lys错义突变,而正常对照组同一位置未见异常．4个家系临床表型不同．结论：β—MHC基因Gln893Lys突变是中国人肥厚型心肌病的致病突变之一,其临床表型的异质性,提示多因素参与了肥厚型心肌病的发生和发展．     

高通量测序鉴定肥厚型心肌病患儿致病突变

目的利用目标基因靶向捕获高通量测序方法鉴定肥厚型心肌病(HCM)患儿的致病突变,分析基因型与临床表型的关系。方法对1例14岁男性HCM患儿进行血液与临床资料收集。提取其全血基因组DNA、文库制备,靶向富集8个编码肌小节蛋白的HCM的致病基因,并行高通量测序。通过生物信息学分析筛选致病突变。用1代测序来验证2代测序发现的致病突变位点。结果患儿有晕厥史,左心室严重肥厚,心电图呈传导阻滞。目标基因捕获高通量测序筛查致病突变的结果经与公共数据库和内部健康人测序数据库对比,发现致病突变位点MYH7R869C。此位点检测结果与Sanger测序结果完全一致。结论利用目标基因捕获测序技术可筛选出HCM致病突变MYH7 R869C。携带此突变的患儿临床表型严重。MYH7 R869C突变可能是我国HCM患儿的突变热点。     

肥厚型心肌病肌钙蛋白T基因突变的研究

目的调查中国人群肥厚型心肌病(HCM)患者基因突变的发生情况并对基因型与临床表型之间的关系进行分析。方法对71例HCM先证者及100名正常对照的聚合酶链反应扩增产物行单链构象多态性分析,于肌钙蛋白T(TNNT2)基因第8、9、10、11、16外显子范围内寻找突变位点,并了解基因型明确的HCM患者的临床特点。结果 在1例患者TNNT2基因的第9外显子上发现了一个新的错义突变位点124A>C(K124N)。由于在100名正常对照中未见该错义突变,故我们认为此突变位点为该患者的致病基因位点。该患者38岁起出现临床症状,超声表现为室间隔中度肥厚,家族中无心源性猝死发作史。结论肌钙蛋白T的尾端对于其连接功能起着至关重要的作用,该区域的基因突变可导致肥厚型心肌病的发生。证实了该病具有异质性遗传的特点。     

一个汉族肥厚型心肌病家系中首次发现肌球连接蛋白-C基因Arg346fs突变

目的研究中国人家族性肥厚型心肌病(HCM)的致病基因突变位点,分析基因型与临床表型的相互关系。方法对5个经过MYH7基因扫描未发现异常的家族性HCM的先证者进行肌球连接蛋白-C基因(MYBPC3)扫描,聚合酶链反应(PCR)扩增其功能区外显子片断,双脱氧末端终止法测序。对阳性结果者进行家系中其他成员筛查,并分析患者临床表型特点。结果在1个家系中发现MYBPC3基因的13号外显子的Arg346fs突变,而正常对照组同一位置未见异常,Arg346fs突变为我国患者中首次发现。结论MYBPC3基因为我国家族性HCM的的致病基因之一。其临床表型的异质性提示多因素参与了HCM的发生及外显。