中国两地区人群的日本人苯丙氨酸羟化酶基因突变差异的研究

为探讨不同地区苯丙酮尿症（ＰＫＵ）患者ＰＡＨ基因突变特征并寻找安全可靠的检测ＰＡＨ基因突变方法，应用碱性磷酸酶标记的ＡＳＯ探针杂交技术和生物素标记的双脱氧核糖苷酸的ＤＮＡ测序技术，对２９例中国北方和台湾地区及日本ＰＫＵ患者ＰＡＨ基因突变进行了检测。检出１１种点突变，其中外显子７、６、１２和３是最常见的突变，分别占３７．９％、１５．５％、１３．８％和１０．３％。在１例台湾ＰＫＵ患者中检出一新生突变（     

中国两地区人群和日本人苯丙氨酸羟化酶基因突变差异的研究

为探讨不同地区苯丙酮尿症（ＰＫＵ）患者ＰＡＨ基因突变特征并寻找安全可靠的检测ＰＡＨ基因突变方法，应用碱性磷酸酶标记的ＡＳＯ探针杂交技术和生物素标记的双脱氧核糖核苷酸的ＤＮＡ测序技术，对２９例中国北方和台湾地区及日本ＰＫＵ患者ＰＡＨ基因突变进行了检测。检出１１种点突变，其中外显子７、６、１２和３是最常见的突变，分别占３７．９％、１５．５％、１３．８％和１０．３％。在１例台湾ＰＫＵ患者中检出一新生突变（Ｒ１５８Ｗ）。说明中国北方和台湾地区及日本ＰＫＵ患者与高加索人ＰＡＨ基因起源不同，而同属于东方人群的ＰＫＵ患者之间的突变差异可能是由于种族进化中的遗传漂变所致。碱性磷酸酶标记的ＡＳＯ杂交技术和生物素标记的ＤＮＡ测序技术是一种安全可靠的检测基因突变的方法。     

中国南方人苯丙氨酸羟化酶基因外显子7点突变及其频率分析

采用ＰＣＲ、变性梯度凝胶电泳及ＤＮＡ直接序列分析等突变分析方法，对５８例中国南方人苯丙酮尿症的苯丙氨酸羟化酶外显子７进行了分析，共发现５种突变位点：ＩＶＳ６ｎｔ－１、Ａｒｇ２４１Ｃｙｓ、Ａｒｇ２４３Ｇｌｕ、Ｖａｌ２４５Ｖａｌ及Ａａｌ２４５Ｖａｌ及Ａｒｇ２５２Ｇｌｎ，其频率分别为３／１１６、１／１１６、１１／１１６、７／１１６及４／１１６。结果提示南方人群ＰＫＵ基因突变位点有别于北方人群。     

云南经典PKU基因外显子4,10和12突变的检测

目的：探讨云南经典ＰＫＵ的基因突变特征。方法：应用ＰＣＲˉＳＣＰ和ＰＣＲ－循环测序技术对云南１３个ＰＫＵ家系１４名患儿的ＰＡＨ基因外显子４、１０和１２进行了检测。结果：Ｒ４１３Ｐ、Ｗ３２６Ｘ的突变频率分别是７１４％、３５７％；Ａ／Ｃ杂合频率是１０７１％，同时检测到外显子４的３种异常带型。结论：云南ＰＫＵ患者的基因突变不同于北方人群，Ｐ４１３Ｐ、Ａ／Ｃ杂合率约为北方人群突变的１／２；Ｗ３２６Ｘ则高于北方人群；外显子４的突变也可能高于北方人群。     

云南苯丙氨酸羟化酶基因点突变及外显子5内新突变Y166X(C→G)的鉴定

目的研究云南苯丙氨酸羟化酶基因点突变分布概况,以提高该地区苯丙酮尿症（ＰＫＵ）的基因诊断率。方法应用ＰＣＲ－ＡＳＯ探针斑点杂交,ＰＣＲ－ＳＳＣＰ、ＡＳＰＣＲ和ＤＮＡ直接测序等技术,对１３／１４名云南籍ＰＫＵ患儿的苯丙氨酸羟化酶（ＰＡＨ）基因外显子４、５、６、７、１０、１１和１２进行了鉴定分析。结果共检出５种错义突变：Ｒ２４３Ｑ（５／２６）、Ｙ２０４Ｃ（３／２８）、Ｒ４１３Ｐ（２／２８）、Ｔ４１８Ｐ（１／２８）及Ｇ２４７Ｖ（１／２６）,３种无义突变Ｙ１６６Ｘ（Ｃ→Ｇ）（２／２６）、Ｗ３２６Ｘ（１／２８）及Ｙ３５６Ｘ（２／２６）和１种静止突变Ｖ３９９Ｖ（２／２６）。经检索国际ＰＡＨ基因突变数据库,其中Ｙ１６６Ｘ（Ｃ→Ｇ）为首次发现的新突变。结论云南藉ＰＫＵ与中国北方人群有相类似的最常见的ＰＡＨ基因突变类型（Ｒ２４３Ｑ、Ｙ２０４Ｃ、Ｙ３５６Ｘ、Ｖ３９９Ｖ和Ｒ４１３Ｐ）,但与南方人群ＰＡＨ基因突变特点则不同。该发现有助于提高云南ＰＫＵ的基因诊断率,并对我国ＰＡＨ基因突变不同地区及人群的分布、起源研究有参考价值。     

非同位素逆相点杂交方法检测苯丙酮尿症突变基因

目的建立一种简便、准确和快速的筛查苯丙酮尿症（ＰＫＵ）突变基因的方法。方法应用生物素渗入的聚合酶链反应扩增中国人ＰＫＵ患者常见突变位点：Ｙ２０４Ｃ（ｅｘｏｎ６，Ｅ６）、Ｒ２４３Ｑ（Ｅ７）、Ｙ３５６Ｘ（Ｅ１１）和Ｒ４１３Ｐ（Ｅ１２）所在的４个外显子区域，扩增标记产物再与固定于同一张膜上的等位基因特异性寡核苷酸探针进行逆相点杂交（ＲＤＢ），用碱性磷酸酶显色法检测杂交信号以确定突变类型。结果建立了检测以上突变位点的非同位素逆相点杂交方法，并对５例就诊的ＰＫＵ患者进行了ＲＤＢ检测，查明３例携带Ｒ２４３Ｑ突变，其中１例还带有Ｙ３５６Ｘ突变，用单链构象多态性方法验证了上述结果。结论该方法适用于对中国人ＰＫＵ患者进行常见突变位点的快速筛查     

Wilson's病8号外显子突变研究

目的对中国人ＷＤ基因８号外显子进行突变分析。方法对中国人Ｗｉｌｓｏｎ＇ｓ病（Ｗｉｌｓｏｎ＇ｓｄｉｓｅａｓｅ,ＷＤ）４５例患者以及２０例正常人的ＡＴＰ７Ｂ基因８号外显子进行ＳＳＣＰ分析,对有异常者进行测序,根据突变点序列设计合适的内切酶对所有患者进行酶切分析。结果正常组未见异常。患者组发现ｅｘ－ｏｎ８有泳动异常,序列分析证实Ｇ２２７３Ｔ置换,即Ａｒｇ７７８Ｌｅｕ突变。用限制性内切酶ＭｓｐⅠ对４５例患者以及２０例正常对照进行该位点酶切分析,表明正常组未见异常,患者组有２例突变纯合子,占患者总数４．４％,１１例杂合子,占１２．２％。外显子８的Ａｒｇ７７８Ｌｅｕ突变率占ＷＤ突变基因的１６．６７％。检测了２个突变家系。结论８号外显子突变可能是中国人ＷＤ发病的较重要原因。     

苯丙酮尿症的临床研究（附120例临床分析）

苯丙酮尿症（ＰＫＵ）是最常见的先天性代谢病之一，从１９８４年１１月至１９９３年４月收治ＰＫＵ患儿１２０例，其中６１例用无苯丙氨酸（ＰＡ）奶粉和低ＰＡ奶粉加低ＰＡ饮食疗法为奶粉治疗组，５９例用单纯饮食疗法为非奶粉组，年龄分为０－１月、１－３月、３－６月、６－１岁，１－２岁、＞２岁。两组同时做智商和脑电图（ＥＥＧ），奶粉治疗组０－３组治疗者智商及ＥＥＧ均正常，３－６月智商在正常低限，＞６月者低于正常，但有少数坚持合理治疗者，智商有的达正常水平。说明对于ＰＫＵ患儿的早期诊断和早期治疗是十分必要的，两组疗效比较有显著差异（Ｐ＜０．０５），两组ＥＥＧ异常发生率分别为５２．４６％，６０．１％差异显著（ｔ＝３．１８７６６，Ｐ＜０．０１），对于６月以下患儿用特殊奶粉加低ＰＡ饮食大大低于单纯饮食疗法，强调用无或低ＰＡ奶粉治疗是防止智力低下，改善预后的重要手段。     

用PCR-STR、ASPCR、PCR-SSCP技术对PKU患者进行产前基因诊断

为探讨苯丙酮尿症的产前诊断途径，应用３种基因诊断方法从不同角度对１６个苯丙酮尿症家系的苯丙氨酸羟化酶基因进行了分析。（１）聚合酶链反应－短串联重复序列连锁分析：通过扩增苯丙氨酸羟化酶基因内含子３中含短串联重复序列的ＤＮＡ区域，并进行扩增片段长度多态性分析，结果表明：能进行准确产前基因诊断者占６２．５％，能进行５０％排除诊断的家系占３７．５％，１例风险胎儿的产前基因诊断和另一家系生后１５天婴儿的症前诊断获得成功；（２）多重等位基因特异性聚合酶链反应，对苯丙氨酸羟化酶基因中两种最常见的突变点分析结果为：Ａｒｇ２４３Ｇｌｕ检出率为１９％，Ａｒｇ４１３Ｐｒｏ检出率为１２％；（３）应用聚合酶链反应－单链构象多态性分析，不仅检出３例已知的基因突变，还发现２例可能为新的基因突变，诊断率达到４０％。为苯丙酮尿症的产前基因诊断提供了依据。     

北方汉族人群PAH基因STR多态性分析及PKU产前基因诊断研究

苯丙酮尿症（ＰＫＵ）是由肝脏苯丙氨酸羟化酶（ＰＡＨ）缺陷引起的常染色体隐性遗传病。临床主要表现为智力低下。研究表明，ＰＫＵ的分子基础主要是ＰＡＨ基因的点突变。到１９９６年，汇集２８个国家研究成果的ＰＡＨ基因突变数据库已登记３２０余种ＰＡＨ突变［１］。...     

16例苯丙酮尿症PAH基因Exon7突变的检测

应用选择突变扩增系统方法对１６例苯丙酮尿症患儿ＰＡＨ基因Ｅｘｏｎ７区域的多聚酶链反应扩增产物进行了突变位点的检测。结果在３２个突变位点中Ｒ２４３Ｑ和Ｒ２６１Ｑ突变位点的检出率分别为４６．８８％和９．３８％，二者占整个突变位点的５６．２５％。表明ＰＡＨ基因Ｅｘｏｎ７突变在中国苯丙酮尿症患者中具有很高的发生频率。     

河南地区苯丙酮尿症患者苯丙氨酸羟化酶基因突变研究

目的 了解河南地区苯丙酮尿症(phenylketonuria,PKU)患者苯丙氨酸羟化酶(phenylalanine hydroxylase,PAH)基因突变情况,以便为苯丙酮尿症产前诊断和遗传咨询提供理论依据.方法 应用PCR产物直接测序对47例PKU患者及其父母PAH基因第1～13外显子及其两侧内含子进行序列分析.结果 在94条染色体中共检测到了83个PAH基因突变位点,检出率为88.3%(83/94),共发现了25种突变,其中突变E79fX13、H271R和D415Y国内外未见报道,突变VS10-14C＞G为国内首次报道.河南地区PKU患者的PAH基因突变集中在第6、7和11外显子,常见的7种突变是p.R243Q(20.5%)、EX6-96A＞G(12.0%)、p.Y356X(9.6%)、VS4-1G＞A(9.6%)、p.R111X(8.4%)、p.V399V(8.4%)、p.R413P(7.2%).结论 河南地区PKU患者PAH基因突变与中国其他地区相似,通过PAH基因直接测序可对大部分的PKU家系进行产前诊断.

Abstract：

Objective To study the characteristics of the phenylalanine hydroxylase gene (PAH)mutations in patients with phenylketonuria (PKU) in Henan province, in order to provide basic information for genetic counseling and prenatal diagnosis. Methods Mutations of the PAH gene were detected in exons 1-13 with flanking introns of PAH gene by PCR and DNA sequencing in 47 families with PKU. Results A total of 25 different mutations were detected in 83 out of 94 PAH alleles (88. 3%). Among them,E79fX13, H271R and D415Y have not been reported previously. It was the first time that IVS10-14C＞Gmutation was reported in Chinese PKU population. The mutations p. R243Q, EX6-96A＞G, p. Y356X,IVS4-1G＞A, p. R111X, p. V399V and p. R413P, were the prevalent mutations with relative frequencies of 20. 5 %, 12.0%, 9.6%, 9. 6%, 8. 4%, 8. 4% and 7.2% respectively. Conclusion The mutations of the PAH gene in patients with classical phenylketonuria in Henan province were similar to that in other areas of China. Prenatal gene diagnosis for PKU by PAH gene sequencing is efficient for most PKU families.     

Genotype and phenotype correlation of phenylalanine hydroxylase deficiency among patients from Henan北大核心CSCD

Objective: To delineate the mutation spectrum of phenylalanine hydroxylase (PAH) gene among patients affected with phenylalanine hydroxylase deficiency (PAHD) in Henan Province of China, and to explore the correlation between the genotype and the phenotype. Methods: A total of 155 affected children were recruited. Potential mutation of the PAH gene were analyzed by direct sequencing. The genotype - phenotype correlation was analyzed by matching the expected and observed phenotypes. Results: Over 72 mutations and 108 genotypes have been identified. There were 7 homozygous mutations, including 1 case with EX6-96A>G/EX6-96A>G, 1 with R241C/R241C, 1 with R413P/R413P, and 4 with R243Q/R243Q. Among these, 6 patients have presented classic PKU phenotypes, except for a R241C/R241C genotype which has led to mild PKU. In 104 patients carrying compound PAH mutations, 52 were classic, 34 were mild and 39 had mild HPA. Patients who were heterozygous for EX6-96A>G/R241C, R243Q/A434D, EX6-96A>G/R413P and EX6-96A>G/ R241C were found with both the classic PKU and mild PKU phenotypes. Common mutations associated with mild HPA have included R53H, R243Q, V399V and H107R. The common mutations associated with mild PKU included R243Q, R241C, EX6-96A>G, and IVS4-1G>A. The prevalent mutations in classic PKU were R243Q, EX6-96A>G and V399V. The consistency between prediction of the biochemical genotype and observed phenotype was 77.78%, especially in classic PKU, the consistency was up to 82.14%. Significant correlations were disclosed between pretreatment levels of phenylalanine and AV sum (r= -0.6729, P<0.01). Conclusion: The mutation spectrum of PAH gene in Henan seems to differ from that of other regions. Independent assortment of mutant alleles may result in a complex genotype-phenotype correlation, but the genotypes of PAHD patients have correlated with the phenotype. © 2016, West China University of Medical Sciences. All rights reserved.     

Toll-like receptor (TLR) 2 and 4 mutations in periodontal disease

Toll-like receptors (TLR) are signal molecules essential for the cellular response to bacterial cell wall components. Different functional effective polymorphisms for the TLR 4 gene (Asp299Gly; Thr399Ile) and for the TLR 2 gene (Arg677Trp, Arg753Gln) have recently been described that are associated with impaired lipopolysaccharide signal transduction. A total of 122 patients with chronic periodontal disease and 122 healthy unrelated controls were genotyped for the Asp299Gly and Thr399Ile polymorphism of the TLR 4 gene and the Arg677Trp and Arg753Gln mutation of the TLR 2 gene. The mutations were identified with polymerase chain reaction followed by restriction fragment length polymorphism (RFLP) analysis. The prevalence of the Asp299Gly and the Thr399Ile mutant allele was 4.1% (10/244) and 4.5% (11/244) among periodontitis patients. For the healthy controls the prevalence was 3.3% (8/244) for the Asp299Gly (P = 0.810) and 3.7% (9/244) for the Thr399Ile mutant allele (P = 0.819). The Arg753Gln mutant allele was found in 2.9% (7/244) of the periodontitis subjects as compared to 4.1% (10/244) in the control group (P = 0.622). The Arg677Trp mutant allele was not found in any of the study subjects. Unlike in ulcerative colitis there was not observed an association between chronic periodontitis and the various mutations of the TLR 2 and 4 gene.     

Genetic diagnosis of phenylketonuria: identification of the mutations of phenylalanine hydroxylase gene by PCR direct sequencing]

To investigate the mutations of the phenylalanine hydroxylase (PAH) gene in Orientals, direct sequencing was conducted on DNA fragments amplified by the polymerase chain reaction, using solid phase technology involving the biotin-streptavidin system. Four mutations possibly associated with phenylketonuria (PKU) were identified in a Chinese and four Japanese patients. A novel Arg158 (CGG)-to-Trp158 (TGG) mutation was identified in exon 5 of the PAH gene in a Chinese PKU patient. The second change was due to a G-to-A transversion at the last base of intron 4. The third change was a compound heterozygote; one mutation was a G-to-A transversion at the last base of intron 4. The other was a G-to-C transversion at the second base of codon 413, which resulted in a substitution of Arg(CGC) by Pro(CCC) in exon 12. The last change was due to a Tyr204(TAT) -to-cys204(TGT) mutation in exon 6 of the PAH gene in two Japanese. This preliminary study revealed a novel PKU mutation and considerable genetic heterogeneity in the PAH gene among Orientals.     

Founder TIGR/myocilin mutations for glaucoma in the Québec population

Primary open-angle glaucoma (POAG) is a complex disorder characterized by a progressive and treatable degeneration of the optic nerve. TIGR/myocilin (MYOC) gene mutations are found in approximately 4% of all POAG patients. Populations with frequent founder effects, such as the French-Canadians, offer unique advantages to implement genetic testing for the disorder. To assess molecular diagnosis for POAG in this population, we determined the prevalence of TIGR/MYOC mutations in 384 unrelated glaucoma patients, 38 ocular hypertensive subjects and 18 affected families (180 patients). We further analyzed the clinical features associated with these variations. Nine coding sequence variants were defined as mutations causing mostly, but not exclusively, POAG. Four families segregated distinct mutations (Gly367Arg, Gln368Stop, Lys423Glu and Pro481Leu), while 14 unrelated glaucoma patients harbored six known mutations (Thr293Lys, Glu352Lys, Gly367Arg, Gln368Stop, Lys423Glu and Ala445Val) and two novel (Ala427Thr and Arg126Trp). The frequencies of these mutations were respectively 3.8% and 22.2% in the unrelated and family studies. The Gly367Arg and Lys423Glu variants caused the earliest ages at onset. When achievable, assessment of relatives of unrelated mutation carriers showed the Arg126Trp and Gly367Arg to be familial. Characteristic allele signatures, indicative of specific founder effects, were observed for five of the six mutations conveyed by at least two patients. Recombination probability estimates suggested that the French-Canadian population had most probably inherited these six mutations from 7-10 Québec settlers. Our data demonstrated that genetic screening for TIGR/MYOC mutations should be offered to glaucoma families and to close relatives of unrelated patients aware of a family history for the disorder.     

Frequency and distribution of phenylketonuric mutations in Orientals.

The frequency and distribution of eight mutations (R111X, IVS4nt-1, Y204C, R243Q, IVS7nt-2, W326X, Y356X, and R413P) in the phenylalanine hydroxylase gene of Orientals in Japan and Korea were examined by allele-specific oligonucleotide hybridization. The mutant alleles comprised 54 and 55% of the phenylketonuria (PKU) chromosomes examined in 36 patients in Japan and 10 patients in Korea, respectively. The spectrum of PKU mutations in Japan was similar to that in China, particularly in northern China, but different from that in Korea. The IVS4nt-1 mutation had a high frequency in Korea and southern China, due to the result of the founder effect and genetic drift. The R413P mutation, which may have originated in the regions surrounding the Baikal, expanded to northern China and Japan. We did not find Caucasian mutations in the Japanese or Korean PKU chromosomes. Thus, PKU mutations occurred after racial divergence between Caucasians and Mongoloids, and there were different founding populations for PKU in the two populations.     

Insight into vitamin B6‐dependent epilepsy due to PLPBP (previously PROSC) missense mutations

Vitamin B₆‐dependent genetic epilepsy was recently associated to mutations in PLPBP (previously PROSC), the human version of the widespread COG0325 gene that encodes TIM‐barrel‐like pyridoxal phosphate (PLP)‐containing proteins of unclear function. We produced recombinantly, purified and characterized human PROSC (called now PLPHP) and its six missense mutants reported in epileptic patients. Normal PLPHP is largely a monomer with PLP bound through a Schiff‐base linkage. The PLP‐targeting antibiotic d ‐cycloserine decreased the PLP‐bound peak as expected for pseudo‐first‐order reaction. The p.Leu175Pro mutation grossly misfolded PLPHP. Mutations p.Arg241Gln and p.Pro87Leu decreased protein solubility and yield of pure PLPHP, but their pure forms were well folded, similarly to pure p.Pro40Leu, p.Tyr69Cys, and p.Arg205Gln mutants (judged from CD spectra). PLPHP stability was decreased in p.Arg241Gln, p.Pro40Leu, and p.Arg205Gln mutants (thermofluor assays). The p.Arg241Gln and p.Tyr69Cys mutants respectively lacked PLP or had a decreased amount of this cofactor. With p.Tyr69Cys there was extensive protein dimerization due to disulfide bridge formation, and PLP accessibility was decreased (judged from d ‐cycloserine reaction). A 3‐D model of human PLPHP allowed rationalizing the effects of most mutations. Overall, the six missense mutations caused ill effects and five of them impaired folding or decreased stability, suggesting the potential of pharmacochaperone‐based therapeutic approaches.