Mutation screening of the F Ⅷ gene in 10 hemophilia A families

Objective To identify the F Ⅷ gene mutations of patients and suspected female carriers in 10 Hemophilia A (HA) families, and to guide the prenatal diagnosis. Methods PCR, denaturing high performance liquid chromatogramphy(DHPLC) and DNA sequencing technologies were applied to screen the FⅧ gene of 8 HA patients and 12 suspected female carriers in the 10 families. Linkage analysis was performed by using St 14 (DXS 52), intron 13 (CA)n and EX18/Bcl Ⅰ of the FⅧ gene in the HA families.In prenatal diagnosis, we screened the same mutation found in the patients. PCR-restriction fragment length polymorphism was applied to detect the new missense mutations of F Ⅷ gene in 100 unrelated healthy individuals to exclude the possibility of polymorphism. Results (1) Five missense mutations, 3 frameshift mutations, 2 nonsense mutations and 2 single nucleotide polymorphism(SNP) were identified in 10 the HA families. Among them, c. 878A＞G, c. 1015A＞G, c. 6870G＞T, c. 1282delA, c. 3072_3073insT, c. 4880_4881insA and c. 5000G＞A were novel mutations or polymorphism. No missense mutations c. 878A＞G, c.1015A＞G and c. 6870G＞T, were found in the 100 healthy unrelated controls. (2) Nine suspected female carriers were confirmed at the gene level. (3) X risk chromosome could be determined in 4 HA families by genetic linkage analysis. (4) Among the four fetuses for prenatal diagnosis, 2 were normal, 1 was carrier and the remaining 1 was a patient. Conclusion Six novel mutations, i. e. , c. 878A＞G, c. 1015A＞G, c.6870G＞T, c. 1282delA, c. 3072_3073insT and c. 4880_4881insA, were identified in this study. PCR,DHPLC and DNA sequencing could be used to screen the gene mutations of HA patients, to carry out carrier detection and prenatal diagnosis of HA families efficiently, by combining with restriction endonuclease analysis and genetic linkage analysis.     

Mutation screening of the F Ⅷ gene in 10 hemophilia A families

Objective To identify the F Ⅷ gene mutations of patients and suspected female carriers in 10 Hemophilia A (HA) families, and to guide the prenatal diagnosis. Methods PCR, denaturing high performance liquid chromatogramphy(DHPLC) and DNA sequencing technologies were applied to screen the FⅧ gene of 8 HA patients and 12 suspected female carriers in the 10 families. Linkage analysis was performed by using St 14 (DXS 52), intron 13 (CA)n and EX18/Bcl Ⅰ of the FⅧ gene in the HA families.In prenatal diagnosis, we screened the same mutation found in the patients. PCR-restriction fragment length polymorphism was applied to detect the new missense mutations of F Ⅷ gene in 100 unrelated healthy individuals to exclude the possibility of polymorphism. Results (1) Five missense mutations, 3 frameshift mutations, 2 nonsense mutations and 2 single nucleotide polymorphism(SNP) were identified in 10 the HA families. Among them, c. 878A＞G, c. 1015A＞G, c. 6870G＞T, c. 1282delA, c. 3072_3073insT, c. 4880_4881insA and c. 5000G＞A were novel mutations or polymorphism. No missense mutations c. 878A＞G, c.1015A＞G and c. 6870G＞T, were found in the 100 healthy unrelated controls. (2) Nine suspected female carriers were confirmed at the gene level. (3) X risk chromosome could be determined in 4 HA families by genetic linkage analysis. (4) Among the four fetuses for prenatal diagnosis, 2 were normal, 1 was carrier and the remaining 1 was a patient. Conclusion Six novel mutations, i. e. , c. 878A＞G, c. 1015A＞G, c.6870G＞T, c. 1282delA, c. 3072_3073insT and c. 4880_4881insA, were identified in this study. PCR,DHPLC and DNA sequencing could be used to screen the gene mutations of HA patients, to carry out carrier detection and prenatal diagnosis of HA families efficiently, by combining with restriction endonuclease analysis and genetic linkage analysis.     

河南地区苯丙酮尿症患者苯丙氨酸羟化酶基因突变研究

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.     

河南地区苯丙酮尿症患者苯丙氨酸羟化酶基因突变研究

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.     

两个新RUNX2基因突变引起家族性锁骨颅骨发育不全

Objective To identify the RUNX2 gene mutation in two unrelated Chinese families with cleidocranial dysplasia (CCD), and to assess the feasibility of gene diagnosis for patients with CCD. Methods Genomic DNA was isolated from peripheral blood samples of 4 patients and 4 healthy members in the two pedigrees as well as 102 unrelated healthy controls. All 7 coding exons and their flanking intronic sequences of the RUNX2 gene were amplified by PCR, then the PCR products were sequenced bi-directionally. The sequencing results were compared with normal sequences in GenBank to identify the mutation. The mutation was confirmed by RFLP with restriction endonuclease. Results In one family, a novel heterozygous missense mutation c. 346T＞A (W116R) in exon 1 of the RUNX2 gene was detected in the two affected individuals, and the mutation was further confirmed with Bsr Ⅰ restriction endonuclease digestion. In the other family, a novel nonsense mutation c. 610A＞T (K204X) was identified in the two patients. No above sequence change was found in the 102 healthy controls. Conclusion Two novel RUNX2 mutations were found in two unrelated Chinese families with cleidoeranial dysplasia. The identification of these mutations further extended the mutation spectrum of RUNX2 gene and will facilitate prenatal diagnosis and gene diagnosis of CCD.     

两个新RUNX2基因突变引起家族性锁骨颅骨发育不全

Objective To identify the RUNX2 gene mutation in two unrelated Chinese families with cleidocranial dysplasia (CCD), and to assess the feasibility of gene diagnosis for patients with CCD. Methods Genomic DNA was isolated from peripheral blood samples of 4 patients and 4 healthy members in the two pedigrees as well as 102 unrelated healthy controls. All 7 coding exons and their flanking intronic sequences of the RUNX2 gene were amplified by PCR, then the PCR products were sequenced bi-directionally. The sequencing results were compared with normal sequences in GenBank to identify the mutation. The mutation was confirmed by RFLP with restriction endonuclease. Results In one family, a novel heterozygous missense mutation c. 346T＞A (W116R) in exon 1 of the RUNX2 gene was detected in the two affected individuals, and the mutation was further confirmed with Bsr Ⅰ restriction endonuclease digestion. In the other family, a novel nonsense mutation c. 610A＞T (K204X) was identified in the two patients. No above sequence change was found in the 102 healthy controls. Conclusion Two novel RUNX2 mutations were found in two unrelated Chinese families with cleidoeranial dysplasia. The identification of these mutations further extended the mutation spectrum of RUNX2 gene and will facilitate prenatal diagnosis and gene diagnosis of CCD.     

Mutation analysis of 11 Chinese patients with attenuated mucopolysaccharidosis type Ⅰ

Objective Mucopolysaccharidosis type Ⅰ (MPS Ⅰ ) is an autosomal recessive diseaseresulting from the deficiency in the lysosomal enzyme α-L-iduronidase (IDUA). The present study was conducted to identify IDUA gene mutations in attenuated (MPS Ⅰ H/S and MPS Ⅰ S) patients with MPS Ⅰin northern China. Methods Fourteen exons with adjacent intronic sequences of the IDUA gene in 11 MPS Ⅰ patients were amplified by polymerase chain reaction (PCR), and the PCR products were sequenced directly and origin analysis was conducted. Results Seven mutations were detected in the 11 MPS Ⅰ patients, i.e., c. 236 C＞T(p. A79V), c. 266 G＞A(p. R89Q), c. 265 C＞T(p. R89W), c. 532G＞A(p.E178K), c. 589G＞A(p. G197S), c. 1037T＞G(p. L346R), and c. 1877 G＞A(p. W626X). All of them were known mutations. Six patients were homozygotes and 1 was heterozygote with nonsense mutation. In addition, 9 reported single nucleotide polymorphism (SNP) were detected, i. e., p. A8, p. A20, p. H33Q,p. R105Q, p. A314, p. A361T, p. T388, p. T410 and p. V454I. Conclusion The mutation spectrum of the IDUA gene in attenuated MPS Ⅰ Chinese patients may be different from that in patients from other countries.     

Mutation analysis of 11 Chinese patients with attenuated mucopolysaccharidosis type Ⅰ

Objective Mucopolysaccharidosis type Ⅰ (MPS Ⅰ ) is an autosomal recessive diseaseresulting from the deficiency in the lysosomal enzyme α-L-iduronidase (IDUA). The present study was conducted to identify IDUA gene mutations in attenuated (MPS Ⅰ H/S and MPS Ⅰ S) patients with MPS Ⅰin northern China. Methods Fourteen exons with adjacent intronic sequences of the IDUA gene in 11 MPS Ⅰ patients were amplified by polymerase chain reaction (PCR), and the PCR products were sequenced directly and origin analysis was conducted. Results Seven mutations were detected in the 11 MPS Ⅰ patients, i.e., c. 236 C＞T(p. A79V), c. 266 G＞A(p. R89Q), c. 265 C＞T(p. R89W), c. 532G＞A(p.E178K), c. 589G＞A(p. G197S), c. 1037T＞G(p. L346R), and c. 1877 G＞A(p. W626X). All of them were known mutations. Six patients were homozygotes and 1 was heterozygote with nonsense mutation. In addition, 9 reported single nucleotide polymorphism (SNP) were detected, i. e., p. A8, p. A20, p. H33Q,p. R105Q, p. A314, p. A361T, p. T388, p. T410 and p. V454I. Conclusion The mutation spectrum of the IDUA gene in attenuated MPS Ⅰ Chinese patients may be different from that in patients from other countries.     

11例中国人粘多糖贮积症Ⅰ型轻型患者的基因突变检测

目的 对经酶学确诊的粘多糖贮积症Ⅰ型患者进行α-L-艾杜糖苷酸酶(α-L-iduronidase,IDUA)基因突变检测,了解中国北方地区粘多糖贮积症Ⅰ型轻型患者基因突变特点.方法 应用PCR扩增技术及直接测序技术对11例中国北方地区经酶学确诊的粘多糖贮积症Ⅰ型患者IDUA基因14个外显子及相邻区域进行突变筛查,同时进行亲本来源分析.结果 11例患者中检测出7种基因突变:A79V、R89Q、R89w、E178K、G197S、L346R和W626X.7种突变均为已报道过子,11例中6例患者为纯合改变,1例为无义突变杂合子;发现了9种已知多态性位点.结论 中国北方地区粘多糖贮积症Ⅰ型轻型患者IDUA基因的突变特点可能不同于其他国家和地区.

Abstract：

Objective Mucopolysaccharidosis type Ⅰ (MPS Ⅰ ) is an autosomal recessive diseaseresulting from the deficiency in the lysosomal enzyme α-L-iduronidase (IDUA). The present study was conducted to identify IDUA gene mutations in attenuated (MPS Ⅰ H/S and MPS Ⅰ S) patients with MPS Ⅰin northern China. Methods Fourteen exons with adjacent intronic sequences of the IDUA gene in 11 MPS Ⅰ patients were amplified by polymerase chain reaction (PCR), and the PCR products were sequenced directly and origin analysis was conducted. Results Seven mutations were detected in the 11 MPS Ⅰ patients, i.e., c. 236 C＞T(p. A79V), c. 266 G＞A(p. R89Q), c. 265 C＞T(p. R89W), c. 532G＞A(p.E178K), c. 589G＞A(p. G197S), c. 1037T＞G(p. L346R), and c. 1877 G＞A(p. W626X). All of them were known mutations. Six patients were homozygotes and 1 was heterozygote with nonsense mutation. In addition, 9 reported single nucleotide polymorphism (SNP) were detected, i. e., p. A8, p. A20, p. H33Q,p. R105Q, p. A314, p. A361T, p. T388, p. T410 and p. V454I. Conclusion The mutation spectrum of the IDUA gene in attenuated MPS Ⅰ Chinese patients may be different from that in patients from other countries.     

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.     

DXS52(St14)在血友病甲基因诊断中的方法改进及应用

目的 改进DXS52(St14)在血友病甲(hemophilia A,HA)基因连锁分析中的实验方法并应用于基因诊断,报道DXS52位点与FⅧ基因发生重组的2个家系.方法 采用PCR和琼脂糖凝胶电泳对61个非倒位HA家系的DXS52位点进行基因检测,并用FⅧ基因内的Bcl Ⅰ、HindⅢ、Xba Ⅰ、STRl、STRl3、STR22和STR24这7个位点以及DXS52位点对这61个家系进行基因连锁分析.结果 DXS52位点在43个HA家系中可提供信息,可诊断率为70.5%(43/61).其中8个家系仅DXS52单个位点能提供信息,占13.1%;两个家系的DXS52与FⅧ基因发生基因重组.结论 采用新的实验条件可使DXS52位点基因检测得到准确清晰的实验结果.该位点可诊断率高,目前是HA连锁基因分析中不可缺少的诊断位点,但该位点位于FⅧ基因外,与FⅧ基因间存在重组可能,单独应用于诊断时应谨慎.

Abstract：

Objective To improve the experimental method of DXS52 (St14) and apply it to genetic testing for hemophilia A (HA). Methods PCR of DXS52 and agarose gel electrophoresis were performed for genetic testing in 61 non-inversion HA families. Linkage analysis of 7 loci within the FⅧ gene including Bcl Ⅰ , Hind Ⅲ, Xba Ⅰ , STR1, STR13, STR22 and STR24 were also carried out for the 61 families.Results DXS52 can provide information in 43 out of 61 families and the diagnostic rate was 70. 5%. Eight families can be diagnosed only by DXS52 locus, accounting for 13. 1%. Two families were found to have recombination between DXS52 and FⅧ. Conclusion The new experimental conditions can reach accurate and clear results in DXS52 genetic testing. This gene maker has high diagnostic rate, so it is an indispensable linkage analysis method in HA gene diagnosis. More caution should be paid when using the extragenic locus DXS52 to perform gene diagnosis because of its high recombinant rate with FⅧ.     

Clinical and molecular genetic analysis for 7 patients from 5 pedigrees with 17α-hydroxylase/17, 20 lyase deficiency

Objective To investigate the clinical and genetic characteristics of 7 patients from 5 families with 17α-hydroxylase/17, 20 lyase deficiency (17OHD) and the CYP17A1 mutation in Chinese. Methods Clinical features and laboratory data were collected from 5 families with 17OHD. PCR direct sequencing was performed to screen the mutation of CYP17A1 gene of the patients. Polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP) and sequencing were performed to screen the mutations of CYP17A1 gene in 288 healthy individuals from Shandong province. Results Seven patients (5 of them were 46, XX; 2 were 46, XY) had typical clinical presentation of sexual infantilism, hypertension and hypokalemia. Hormone profile indicated decreased plasma cotisol and sex hormones, and elevated blood adrenocorticotrophic hormone (ACTH). TAC329AA and H373L in exon 6 and D487_ F489del in exon 8 were identified from the patients. One heterozygote for D487_F489del was identified in 288 healthy controls. Conclusion The TAC329AA and D487_F489del of the CYP17A1 gene were the most frequent mutations in Chinese with 17OHD. There might be certain frequency of heterozygotes for D487_ F489del in Chinese population.     

Clinical and molecular genetic analysis for 7 patients from 5 pedigrees with 17α-hydroxylase/17, 20 lyase deficiency

Objective To investigate the clinical and genetic characteristics of 7 patients from 5 families with 17α-hydroxylase/17, 20 lyase deficiency (17OHD) and the CYP17A1 mutation in Chinese. Methods Clinical features and laboratory data were collected from 5 families with 17OHD. PCR direct sequencing was performed to screen the mutation of CYP17A1 gene of the patients. Polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP) and sequencing were performed to screen the mutations of CYP17A1 gene in 288 healthy individuals from Shandong province. Results Seven patients (5 of them were 46, XX; 2 were 46, XY) had typical clinical presentation of sexual infantilism, hypertension and hypokalemia. Hormone profile indicated decreased plasma cotisol and sex hormones, and elevated blood adrenocorticotrophic hormone (ACTH). TAC329AA and H373L in exon 6 and D487_ F489del in exon 8 were identified from the patients. One heterozygote for D487_F489del was identified in 288 healthy controls. Conclusion The TAC329AA and D487_F489del of the CYP17A1 gene were the most frequent mutations in Chinese with 17OHD. There might be certain frequency of heterozygotes for D487_ F489del in Chinese population.     

Clinical and molecular genetic analysis for 7 patients from 5 pedigrees with 17α-hydroxylase/17, 20 lyase deficiency

Objective To investigate the clinical and genetic characteristics of 7 patients from 5 families with 17α-hydroxylase/17, 20 lyase deficiency (17OHD) and the CYP17A1 mutation in Chinese. Methods Clinical features and laboratory data were collected from 5 families with 17OHD. PCR direct sequencing was performed to screen the mutation of CYP17A1 gene of the patients. Polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP) and sequencing were performed to screen the mutations of CYP17A1 gene in 288 healthy individuals from Shandong province. Results Seven patients (5 of them were 46, XX; 2 were 46, XY) had typical clinical presentation of sexual infantilism, hypertension and hypokalemia. Hormone profile indicated decreased plasma cotisol and sex hormones, and elevated blood adrenocorticotrophic hormone (ACTH). TAC329AA and H373L in exon 6 and D487_ F489del in exon 8 were identified from the patients. One heterozygote for D487_F489del was identified in 288 healthy controls. Conclusion The TAC329AA and D487_F489del of the CYP17A1 gene were the most frequent mutations in Chinese with 17OHD. There might be certain frequency of heterozygotes for D487_ F489del in Chinese population.     

Clinical and molecular genetic analysis for 7 patients from 5 pedigrees with 17α-hydroxylase/17, 20 lyase deficiency

Objective To investigate the clinical and genetic characteristics of 7 patients from 5 families with 17α-hydroxylase/17, 20 lyase deficiency (17OHD) and the CYP17A1 mutation in Chinese. Methods Clinical features and laboratory data were collected from 5 families with 17OHD. PCR direct sequencing was performed to screen the mutation of CYP17A1 gene of the patients. Polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP) and sequencing were performed to screen the mutations of CYP17A1 gene in 288 healthy individuals from Shandong province. Results Seven patients (5 of them were 46, XX; 2 were 46, XY) had typical clinical presentation of sexual infantilism, hypertension and hypokalemia. Hormone profile indicated decreased plasma cotisol and sex hormones, and elevated blood adrenocorticotrophic hormone (ACTH). TAC329AA and H373L in exon 6 and D487_ F489del in exon 8 were identified from the patients. One heterozygote for D487_F489del was identified in 288 healthy controls. Conclusion The TAC329AA and D487_F489del of the CYP17A1 gene were the most frequent mutations in Chinese with 17OHD. There might be certain frequency of heterozygotes for D487_ F489del in Chinese population.     

Clinical and molecular genetic analysis for 7 patients from 5 pedigrees with 17α-hydroxylase/17, 20 lyase deficiency

Objective To investigate the clinical and genetic characteristics of 7 patients from 5 families with 17α-hydroxylase/17, 20 lyase deficiency (17OHD) and the CYP17A1 mutation in Chinese. Methods Clinical features and laboratory data were collected from 5 families with 17OHD. PCR direct sequencing was performed to screen the mutation of CYP17A1 gene of the patients. Polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP) and sequencing were performed to screen the mutations of CYP17A1 gene in 288 healthy individuals from Shandong province. Results Seven patients (5 of them were 46, XX; 2 were 46, XY) had typical clinical presentation of sexual infantilism, hypertension and hypokalemia. Hormone profile indicated decreased plasma cotisol and sex hormones, and elevated blood adrenocorticotrophic hormone (ACTH). TAC329AA and H373L in exon 6 and D487_ F489del in exon 8 were identified from the patients. One heterozygote for D487_F489del was identified in 288 healthy controls. Conclusion The TAC329AA and D487_F489del of the CYP17A1 gene were the most frequent mutations in Chinese with 17OHD. There might be certain frequency of heterozygotes for D487_ F489del in Chinese population.     

中国Rett综合征患儿突变基因的亲源分析

Objective To identify the parental origin of methyl-CpG-binding protein 2 (MECP2)gene mutations in Chinese patients with Rett syndrome. Methods Single nucleotide polymorphisms (SNPs) in intron 3 of the MECP2 gene were analyzed by PCR and sequencing in 115 patients with Rett syndrome.Then sequencing of the SNP region was performed for the fathers of the patients who had at least one SNP,to determine which allele was from the father. Then allele-specific PCR was performed and the products were sequenced to see whether the allele from father or mother harbored the mutation. Results Seventy-six of the 115 patients had at least one SNP. Three hot SNPs were found in these patients. They were: IVS3+22C＞G, IVS3+266C＞T and IVS3+683C＞T. Among the 76 cases, 73 had a paternal origin of MECP2 mutations, and the other 3 had a maternal origin. There were multiple types of MECP2 mutation of the paternal origin, including 4 frame shift, 2 deletion and 67 point (56 C＞T, 6 C＞G, 2 A＞G, 2 G＞T and 1 A＞T) mutations. The mutation types of the 3 ptients with maternal origin included 2 frame shift and 1 point (C＞T) mutation. Conclusion In Chinese RTT patients, the MECP2 mutations are mostly of paternal origin.     

中国人黏多糖贮积症ⅣA型家系GALNS基因新突变的鉴定

目的 研究黏多糖贮积症ⅣA型(mucopolysaccharidosis type ⅣA,MPS ⅣA)患者发病的分子遗传学机制,揭示其基因型与表现型的相互关系,为产前基因诊断等创造必要的前提条件.方法 采用尿糖胺聚糖(glycosaminoglycans,GAGs)定性检测法对疑似MPS ⅣA型的先证者进行初诊,然后采用PCR及扩增产物直接测序法对先证者及其家庭成员进行突变检测.在检出GALNS基因c.1567T＞G新突变后,先后建立XspⅠ酶切鉴定法和扩增阻碍突变系统(amplification refractory mutation system,ARMS)快速特异鉴定法,对随机采集的110名正常对照与先证者及其家庭成员的GALNS基因第14外显子进行序列分析,同时采用生物信息学方法对蛋白质二级、三级结构进行预测,以及直接测定患儿GALNS酶活性的方法,对该新突变进行致病性鉴定.结果 先证者尿检呈弱阳性GAGs(±),其GALNS基因第14外显子内存在杂合的c.1567T＞G终止密码突变,第4外显子存在杂合的c.374C＞T错义突变,为两种突变的复合杂合子.其妹突变类型与先证者完全相同,其母仅在第14外显子存在杂合的终止密码突变,为该病的携带者,其父仅在第4外显子存在杂合的错义突变,也为杂合子;第14外显子的PCR产物经XspⅠ酶切后,正常对照组切出28 bp、120 bp、399 bp 3条带,而患者和携带者的母亲均切出28 bp、120 bp、148 bp和399 bp 4条带;用ARMS特异引物扩增后,正常对照组均扩增阴性,而患者及携带者均扩增阳性;蛋白质二级、三级结构预测结果显示:c.1567T＞G变异导致终止密码(TAG)突变为谷氨酸(GAG),使多肽链延长了92个氨基酸残基,导致蛋白质二、三级结构发生明显改变,而正常对照无此变化.酶活性测定的结果显示:患者的GALNS酶活性仅为8.3 nmol/17 h/mg pr,明显低于正常值(正常参考值为41.9～92.1 nmol/17h/mg pr).结论 c.1567T＞G变异是一种新的致病性突变,是引起该家系患儿发病的根本原因.

Abstract：

Objective To study the molecular genetic mechanism of mucopolysaccharidosis type ⅣA(MPS ⅣA), and reveal the relationship between the genotype and phenotype, and provide a basis for prenatal gene diagnosis in the future. Methods A preliminary diagnosis was made by qualitative detection of urinary glycosaminoglycans of the suspected MPS ⅣA proband. Then, mutation detection was performed on the proband and her family members with PCR and direct sequencing of the PCR products. After a novel c.1567T＞G mutation was detected,XspⅠrestriction enzyme digestion and amplification refractory mutation system(ARMS) fast specific identification were established to analyze the sequences of exon 14 in GALNS gene, including 110 randomly selected healthy controls, the proband and other pedigree members. At the same time, bioinformatic approaches for protein secondary, tertiary structure prediction were applied to identify the novel pathologic mutation. Results The proband's urine GAGs test was a weak positive(±),and a c.1567T＞G heterozygous termination codon mutation in exon 14 and a c.374C＞T heterozygous missense mutation in exon 4 were found. The proband was compound heterozygous of the two mutations, so was her younger sister. Her mother was a carrier with only a c.1567T＞G heterozygous mutation in exon 14. Her father had a heterozygous mutation of c.374C>T in exon 4. After XspⅠrestriction enzyme digestion, healthy controls had three bands including 28 bp, 120 bp and 399 bp, while the proband and her mother had four bands consisting of 28 bp, 120 bp,148 bp and 399 bp. For amplification by ARMS specific primers, it was negative for the controls,while it was positive for the proband and the carrier. The results of protein secondary and tertiary structure prediction showed that the c.1567T＞G mutation located in the stop codon, resulted in stop codon (TAG) changing to glutamic acid (GAG), with the peptide chain extending 92 amino acid residues, and secondary and tertiary protein structure change, which were not found in the controls. The result of enzyme assay showed that the activity of GALNS enzyme in the affected child was 8.3 nmol/17h/mg pr, which was obviously lower than the normal value (the normal range is 41.9-92.1 nmol/17h/mg pr). Conclusion These results illustrate that the c.1567 T＞G is a novel pathologic mutation, which is the main cause of the disease in this family.     

中国Rett综合征患儿突变基因的亲源分析

Objective To identify the parental origin of methyl-CpG-binding protein 2 (MECP2)gene mutations in Chinese patients with Rett syndrome. Methods Single nucleotide polymorphisms (SNPs) in intron 3 of the MECP2 gene were analyzed by PCR and sequencing in 115 patients with Rett syndrome.Then sequencing of the SNP region was performed for the fathers of the patients who had at least one SNP,to determine which allele was from the father. Then allele-specific PCR was performed and the products were sequenced to see whether the allele from father or mother harbored the mutation. Results Seventy-six of the 115 patients had at least one SNP. Three hot SNPs were found in these patients. They were: IVS3+22C＞G, IVS3+266C＞T and IVS3+683C＞T. Among the 76 cases, 73 had a paternal origin of MECP2 mutations, and the other 3 had a maternal origin. There were multiple types of MECP2 mutation of the paternal origin, including 4 frame shift, 2 deletion and 67 point (56 C＞T, 6 C＞G, 2 A＞G, 2 G＞T and 1 A＞T) mutations. The mutation types of the 3 ptients with maternal origin included 2 frame shift and 1 point (C＞T) mutation. Conclusion In Chinese RTT patients, the MECP2 mutations are mostly of paternal origin.     

云南傣族儿童中β-地中海贫血HBB基因的变异分布特征

Objective To characterize the distribution of variation in hemoglobin beta gene ( hemoglobin beta gene, HBB )of β-thalassemia in Dai minority group in Yunnan province, and to establish a rapid and economical method for screening β-thalassemia mutation via optimizing ARMS technique.Methods DNA Sequencing was performed to detect variation in 1755 bp DNA fragment containing whole length of hemoglob beta gene ( 1606 bp) from 209 cases of Dai children with β-thalassemia. The primer design and PCR conditions of ARMS (amplification refractory mutation system ) have been optimized for detecting three frequent variations. Results Among 209 samples, there are 9 variations were detected:CD2 T＞ C (50.72%),CD26 G ＞A (35.41%),CD17 A ＞T(12.92%),IVS-Ⅱ-17 C ＞ G (12.44%), IVS-Ⅱ-16 G＞C(11.96%), ⅣS-Ⅰ-30 A＞G(9.57%) , CD6 G ＞A(9.09%) ,CD41-42 (-TCTT) (7. 18%) and CD5 T＞A(1.92%). Three mutations (CD21, CD35 and CD43) were first reported in China. There are 167, out of 209 participants (79.90%), carrying HBB gene variation. Three common mutations (CD2, CD26 and CD17 ) can be efficiently detected by combining condition of both ARMS mismatch primers and 65 ℃ of PCR annealling temperature. Conclusion The distribution of HBB gene variation in the Dai minority group in Yunnan province is different from those of other groups in China. ARMS is an effective, convenient and economical technique for rapid detection of gene mutations of β-thalassemia.