二代测序技术在苯丙酮尿症基因突变检测中的应用

目的利用二代测序技术对新疆地区29名苯丙酮尿症(PKU)汉族患者的苯丙氨酸羟化酶(PAH)基因进行检测,评估二代测序技术在苯丙酮尿症基因诊断中的应用价值,为本地区苯丙酮尿症的基因诊断和产前诊断提供依据。方法应用多重PCR技术富集PAH基因全部外显子及调控区,通过二代测序技术检测突变位点,并以Sanger测序技术验证检测结果。结果共检测了29例PKU样本,在58个PAH等位基因中检测出59个突变基因,共28种突变类型,其中错义突变21种,无义突变3种,剪切位点突变3种,缺失突变1种,以上结果均经Sanger测序验证。结论二代测序技术可应用于苯丙酮尿症相关基因突变的检测,可以作为一种高效、准确、方便和全面的检测方法应用于临床。     

四氢生物蝶呤反应性的苯丙酮尿症研究进展

本文综述对四氢生物蝶呤（BH4）反应性的苯丙氨酸羟化酶（PAH）基因缺陷的苯丙酮尿症（PKU）的研究进展。分析BH4反应性的PAH基因突变，探讨这一现象潜在的发生机制，介绍一种新的临床分类法，并对PKU的BH4替代治疗前景进行展望。     

在一个土耳其苯丙酮尿症病人的PAH基因座位上识别了两个错义突变

苯丙氨酸羟化酶(PAH)缺乏是一种常染色体隐性遗传病,临床分类包括从典型的苯丙酮尿症(PKU)到高苯丙氨酸血症。目前,已能作分子水平的研究,其中在高加索和亚洲群体中已证实了20多种不同的人类PAH基因突变。本文对有单体型3和4的土耳其PKU病人(E1)的DNA做突变分析。用聚合酶链反应(PCR)将病人的PAH基因含13外显子     

新疆回族中苯丙酮尿症基因的突变鉴定

目的探讨新疆回族中苯丙氨酸羟化酶(PAH)基因的突变特点。方法采用PCR产物直接测序的方法,测定7例回族苯丙酮尿症(PKU)患者PAH基因全部外显子及其启动子区域序列。结果在14个回族PAH等位基因中,共检出突变基因10个,包括错义突变5种、无义突变1种、剪切位点突变1种、缺失突变1种,其中的R243Q和R176X为种纯合子突变,这些突变分布于六个外显子,均系在回族中首次发现。检出的突变基因中包含2种新的突变基因类型,即R155H和A300S基因突变,通过查阅国内外文献、查询PAH专业网站及www.pahdb.mcgill.ca国际PAH数据库,证实是国内未见报道的新突变。结论新疆回族PKU患者中PAH基因突变具有明显的异质性特点,我们的研究丰富了PAH基因突变研究的内容,是我国PKU研究中民族资料的重要补充。     

苯丙氨酸羟化酶突变基因型与生化表型分析

目的 探讨苯丙酮尿症(phenylketonuria,PKU)患者苯丙氨酸羟化酶基因(phenylalanine hydroxylase,PAH)突变基因型与生化代谢表型的相关性.方法 用聚合酶链式反应-单链构象多态性、变性高效液相色谱分析和DNA测序法对102例治疗前血清苯丙氨酸(phenylalanine,Phe)高于120 μmol/L患儿基因组DNA进行PAH基因分析,观察突变基因型与生化代谢表型的相关性.结果 (1)生化代谢表型为经典型PKU(Phe>1200μmol/L)69例,中度PKU(Phe 600-1200 μmol/L)31例,轻度PKU(Phe400~600 μmol/L)2例.(2)共检出基因突变41种,基因型75种.(3)纯合突变基因型共9例(8.8%),含R111X/R111X基因型3例,IVS4-1G>A/IVS4-1G>A基因型1例,R243Q/R243Q基因型3例和V399V/V399V基因型2例.9例纯合突变中除1例RZ43Q/R243Q基因型患者的生化代谢表型属中度PKU外,其余8例生化代谢表型均属经典型苯丙酮尿症.(4)复合突变基因型共91 例(89.2%),生化代谢表型属经典型苯丙酮尿症的61例、中度PKU的29例和轻度PKU的1例.(5)复合突变基因型R111X/R243Q和EX6-96A>G(Y204C)/R243Q均可见于经典型苯丙酮尿症和中度PKU生化代谢表型;均属于无效突变等位基因的R111X/V399V基因型、EX6-96A>G/Y356X和EX6-96A>G/V399V生化代谢表型为中度PKU.含不同无效突变相同错义突变的R111X/A165D和R176X/A165D基因型分别表现为中度PKU和经典型苯丙酮尿症表型.结论 本研究中多数患者的突变基因型属复合突变.因突变等位基因的自由组合,使患者的基因型和生化表型之间关系复杂化.虽然大多数突变基因型与生化表型相关,但仍有个别与规律不一致的现象.因此,在PKU的遗传咨询中,依据患者的突变基因型分析评估预后要慎重.同样的基因型,患者表现出不同的生化代谢表型的现象,提示在苯丙氨酸的代谢过程中可能存在还没有被认识的其它影响因素.     

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.     

苯丙氨酸羟化酶基因的六种新型突变

目的　检测中国苯丙酮尿症 ( phenylketonuria ,PKU )患者苯丙氨酸羟化酶 (phenylalaninehy droxylase ,PAH)基因新的突变位点。 方法　应用聚合酶链反应 单链构象多态性及DNA直接测序检测 40例经典型PKU患者和 3 0名正常对照的PAH基因。结果　在PAH基因上共发现 11种突变和 3种多态 ,3 0名正常对照者PAH基因未发现异常。结论　经与国际PAH基因突变数据库比较 ,确认M 2 76K、M 2 76R、2 80insT、IVS10nt 3 2T→A、IVS4nt 4 7C→T是国际上首次发现的突变 ,H 2 90R是中国PKU患者基因上首次发现的新型突变。     

维吾尔族苯丙酮尿症R158Q突变基因杂合子报告

目的报道在新疆维吾尔族家系中检出的苯丙酮尿症(PKU)R158Q突变基因杂合子。方法采用PCR结合单链构象多态性(SSCP)分析技术和PCR产物直接测序方法确定PAH基因突变类型。结果分析患者及其父母PAH第7、6、11、3、12、5外显子基因,发现在外显子5中患者的SSCP电泳行为与正常对照不同而与父亲的电泳条带位置一致,测序结果显示,患者和父亲的PAH基因cDNA第473位发生了G→A点突变,为R158Q突变型杂合子。结论国内在维吾尔族中报道PKU R158Q突变基因杂合子尚属首次。     

四氢生物蝶呤反应性的苯丙酮尿症研究进展

本文综述对四氢生物蝶呤(BH4)反应性的苯丙氨酸羟化酶(PAH)基因缺陷的苯丙酮尿症(PKU)的研究进展。分析BH4反应性的PAH基因突变,探讨这一现象潜在的发生机制,介绍一种新的临床分类法,并对PKU的BH4替代治疗前景进行展望。     

河南省苯丙酮尿症患者苯丙氨酸羟化酶基因突变的构成

目的 了解河南省苯丙酮尿症(phenylketonuria,PKU)患者苯丙氨酸羟化酶(phenylalanine hydroxylase,PAH)基因突变的特点,为临床遗传咨询、基因诊断及产前诊断提供科学依据.方法 应用聚合酶链反应和DNA正反测序技术对34例经典型PKU患者的PAH基因全部13个外显子及两侧部分内含子进行鉴定分析.结果 34例患者共68个PAH等位基因中共检出23种致病突变(包括错义突变12种、无义突变4种、剪接突变4种和缺失3种)和9种其它基因变异.致病基因突变的总检出率为92.65%(63/68).第7外显子的基因突变种类最多,其次是第5外显于和第11外显子.检索PAH基因突变数据库和查阅相关文献,确定有2种突变[A156P和P69_S70delinsP(delCTT)]国际上未见报道,4种突变(IVS2+5G＞C、G332E、IVS10-14C＞G、L367＞Wfs)国内未见报道.结论 河南省PKU患者PAH基因的突变构成及频率与中国其它地区人群稍有不同.     

127例PKU患者PAH基因第12外显子点突变及其频率研究

目的　了解中国人苯丙酮尿症 ( phenylketonuria,PKU)患者的苯丙氨酸羟化酶( phenylalanine hydroxylase,PAH)基因第 12外显子点突变种类和频率。方法　应用单链构象多态性( single strand conformation polymorphism,SSCP)、变性梯度凝胶电泳 ( denaturing gradient gelelectrophoresis,DGGE)、DNA测序分析了 12 7例 PKU患者的 PAH基因第 12外显子点突变种类及频率。结果　 DNA测序分析显示 10例患者存在 R4 13P、S4 11X、R4 0 8W、R4 0 8Q 4种杂合突变 ,其突变频率分别为 2 .76 %、0 .39%、0 .39%、0 .39% ,S4 11X突变为中国人中首次报道。 SSCP分析仅发现 2例 R4 13P杂合突变 ,DGGE分析显示 10例出现 3种类型的异常电泳带型。R4 13P突变在南北方人之间、在经典型 PKU和高苯丙氨酸血症之间的分布差异无显著性。结论　 DGGE对 PAH基因第 12外显子点突变检出率明显高于 SSCP。 DGGE结合 DNA测序是明确 PAH基因第 12外显子点突变种类和频率较好的方法。 R4 13P突变在南北方人中分布无明显差异     

Molecular characterization of phenylketonuria in South Brazil

Phenylketonuria (PKU) is an autosomal recessive disorder due to phenylalanine hydroxylase (PAH) deficiency. The PAH gene, located at 12q22-q24.1, includes about 90kb and contains 13 exons. To date, more than 420 different alterations have been identified in the PAH gene. To determine the nature and frequency of PAH mutations in PKU patients from South Brazil, mutation analysis was performed on genomic DNA from 23 unrelated PKU patients. The 13 exons and flanking regions of the PAH gene were amplified by PCR and the amplicons were analyzed by single strand conformation polymorphism (SSCP). Amplicons that showed abnormal migration patterns were analyzed by restriction endonuclease digestion and/or sequencing. Twenty-two previously reported mutations were identified including R261X, R408W, IVS2nt5g-->c, R261Q, and V388M. Polymorphisms were observed in 48.8% of the PKU patients, the most frequent being IVS2nt19t-->c, V245V, and IVS12nt-35c-->t. In addition, two novel sequence variants were identified: 1378g-->t in the 3(')-untranslated region in exon 13 which may be disease-causing and an intron 12 polymorphism, IVS12nt-15t-->c. The mutation spectrum in the patients from Southern Brazil differed from that observed in patients from other Latin American countries and further defined the molecular heterogeneity of this disease.     

天津及周边地区苯丙氨酸羟化酶基因突变谱和新突变分析

目的 分析天津地区人苯丙氨酸羟化酶(phenylalanine hydroxylase gene,PAH)基因突变谱,明确本地区该基因突变类型和特点,为遗传咨询和产前基因诊断提供科学依据.方法 用聚合酶链反应-单链构象多态、变性高效液相色谱法和DNA测序法对天津及河北等地99例已确诊各种类型苯丙酮尿症患儿基因组DNA进行PAH全基因13个外显子分析.结果 全基因共检出41种突变,含错义突变22种、无义突变7种、剪接位点突变9种和缺失突变3种.其中新突变6种(IVS3nt+1g→a、A165D、Q301X、G344D、P362L和R413G).198个PAH等位基因突变总检出率为93.94%.结论 天津及周边地区PAH基因突变谱广、遗传异质性高,一些常见突变的发生频率与以往报道的地域分布略不同.     

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.     

The molecular basis of phenylketonuria in Latvia

Characterization of the molecular basis of phenylketonuria (PKU) in Latvia has been accomplished through the analysis of 96 unrelated chromosomes from 50 Latvian PKU patients. Phenylalanine hydroxylase (PAH) gene mutations have been analyzed through a combined approach in which R158Q, R252W, R261Q, G272X, IVS10-11G>A and R408W mutations were first screened for by PCR or restriction generating PCR amplification of PAH gene exons 5, 7, 11 and 12 followed by digestion with the appropriate diagnostic enzyme. Subsequently 'broad range' denaturing gradient gel electrophoresis analysis of the 13 PAH gene exons has been used to study uncharacterized PKU chromosomes. A mutation detection rate of 98% was achieved. 12 different mutations were found, with the most frequent mutation, R408W, accounting for 76% of Latvian PKU alleles. Six mutations (R408W, E280K, R158Q, A104D, R261Q and P281L) represent 92% of PKU chromosomes. PAH VNTR and STR alleles have been also identified and minihaplotype associations with PKU mutations were also determined.     

Molecular and phenotypic characteristics of patients with phenylketonuria in Serbia and Montenegro

Phenylketonuria (PKU) is the most common inborn error of amino acid metabolism in Caucasians. PKU is caused by mutations in the gene encoding phenylalanine hydroxylase (PAH) enzyme. Here, we report the spectrum and the frequency of mutations in the PAH gene and discuss genotype-phenotype correlation in 34 unrelated patients with PKU from Serbia and Montenegro. Using both polymerase chain reaction-restriction fragment length polymorphism and 'broad-range' denaturing-gradient gel electrophoresis/DNA sequencing analysis, 19 disease-causing mutations were identified, corresponding to mutation detection rate of 97%. The most frequent ones were L48S (21%), R408W (18%), P281L (9%), E390G (7%) and R261Q (6%), accounting for 60% of all mutant alleles. The genotype-phenotype correlation was studied in homozygous and functionally hemizygous patients. We found that the most frequent mutation, L48S, was exclusively associated with the classical (severe) PKU phenotype. The mutation E390G gave rise to mild PKU. For the mutation R261Q, patients had been recorded in two phenotype categories. Considering allele frequencies, PKU in Serbia and Montenegro is heterogeneous, reflecting numerous migrations over the Balkan Peninsula.     

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.     

山西省经典型苯丙酮尿症患者苯丙氨酸羟化酶基因突变研究

目的 探讨山西省经典型苯丙酮尿症(phenylketonuria,PKU)患者苯丙氨酸羟化酶(phenylalanine hydroxylase,PAH)基因第3、6、7、11和12外显子的突变特征.方法 通过测序及序列比对的方法对山西省59例经典型PKU患者和100名正常儿童PAH基因进行序列分析,以确定其突变位点、性质和突变频率.结果 通过序列分析,发现在患儿和正常儿童中均出现Q232Q(CAA→CAG)、V245V(GTG→GTA)和L385L(CTG→CTC)3种单核苷酸多态性位点(single nucleotide polymorphism,SNP),其中患儿cDNA 696位点的SNP发生率高达96.2%,正常儿童的SNP发生率为97.0%;患儿cDNA 735位点的SNP发生率为76.1%,正常儿童的SNP发生率为77.3%;患儿cDNA1155位点的SNP发生率仅为7.6%,正常儿童SNP发生率为8.3%.正常儿童的其它序列与GenBank中序列比较的无差异.在患儿的基因序列中还发现了16种共计72个突变基因,占全部PAH突变基因的61.0%.第3外显子发现3种突变R111X、H64＞TfsX9和S70 del,突变频率分别为5.1%、0.8%、0.8%;第6外显子仅发现1种突变EX6-96A＞G,突变频率达10.2%;第7外显子中R243Q的突变频率最高,占12.7%,其次是Ivs7+2T＞A,占5.1%,T278I占2.5%,G247V、R252Q、L255S、R261Q、E280K均占0.8%;第11外显子中,Y356 X占5.9%,V399V占5.1%;第12外显子中,R413P占5.9%,A434D占2.5%.在16种突变中,有9种错义突变、3种剪接位点突变、2种无义突变及2种缺失,其中,H64＞TfsX9为本次研究新发现.结论 明确了山西省经典型PKU患者PAH基因第3、6、7、11和12外显子的突变种类和分布等特征,EX6-96A＞G、R243Q可能属于山西人群中PAH基因突变的热点.