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.     

Genetic analysis of two children patients affected with CHARGE syndromeCSCD

Objective To analyze two Chinese pediatric patients with multiple malformations and growth and development delay. Methods Both patients were subjected to targeted gene sequencing, and the results were analyzed with Ingenuity® Variant Analysis™ software. Suspected pathogenic variations were verified by Sanger sequencing. Results High-throughput sequencing showed that both patients have carried heterozygous variants of theCHD7 gene. Patient 1 carried a nonsense mutation in exon 36 (c. 79570T, p. Arg2653 ∗), while patient 2 carried a nonsense mutation of exon 2 (c. 7180T, p. Gln240 ∗ ). Sanger sequencing confirmed the above mutations in both patients, while their parents were of wild-type for the corresponding sites, indicating that the two mutations have happened de novo. Conclusion Two patients were diagnosed with CHARGE syndrome by high-throughput sequencing. © 2018 West China University of Medical Sciences. All rights reserved.     

中国人圆锥角膜患者的TGFBI基因编码区点突变及多态性的检测和分析

Objective To investigate the point mutations and polymorphisms of transforming growth factor β-induced gene (TGFBI) in Chinese patients with keratoconus and discuss the relationship between the feature of gene mutations and single nucleotide polymorphisms of TGFBI gene and keratoconus. Methods Polymerase chain reaction-single strand conformation polymorphism and DNA direct sequencing were performed in 30 keratoconus cases and 30 healthy controls. All 17 exons of the TGFBI gene were analyzed for point mutations and single nucleotide polymorphisms. Results Totally two heterozygous nucleotide changes were identified in exon 12 of the TGFBI gene. The codon 535 is changed from GGA to TGA in 1 patient, leading to a substitution of glycine to a stop codon at the protein level (G535X). The codon 540 is changed from TTT to TTC in 2 patients and 1 control individual, resulting in a nonsense mutation (F54F),and is a single nucleotide polymorphism of the gene. Conclusion Mutation and polymorphisms of the TGFBI gene were detected in Chinese patients with keratoconus in this study. The results suggest that TGFBI gene might play an important role in the pathogenesis of keratoconus.     

中国人圆锥角膜患者的TGFBI基因编码区点突变及多态性的检测和分析

Objective To investigate the point mutations and polymorphisms of transforming growth factor β-induced gene (TGFBI) in Chinese patients with keratoconus and discuss the relationship between the feature of gene mutations and single nucleotide polymorphisms of TGFBI gene and keratoconus. Methods Polymerase chain reaction-single strand conformation polymorphism and DNA direct sequencing were performed in 30 keratoconus cases and 30 healthy controls. All 17 exons of the TGFBI gene were analyzed for point mutations and single nucleotide polymorphisms. Results Totally two heterozygous nucleotide changes were identified in exon 12 of the TGFBI gene. The codon 535 is changed from GGA to TGA in 1 patient, leading to a substitution of glycine to a stop codon at the protein level (G535X). The codon 540 is changed from TTT to TTC in 2 patients and 1 control individual, resulting in a nonsense mutation (F54F),and is a single nucleotide polymorphism of the gene. Conclusion Mutation and polymorphisms of the TGFBI gene were detected in Chinese patients with keratoconus in this study. The results suggest that TGFBI gene might play an important role in the pathogenesis of keratoconus.     

Detection of mutation in embB gene of Mycobacterium tuberculosis from clinical isolates of tuberculous patients in China by means of reverse-dot blot hybridization

The relationship between embB mutation of Mycobacterium tuberculosis and ethambutol (EMB) resistance of the clinical isolates of tuberculous patients in China was investigated by reverse dot blot hybridization (RDBH) in addition to evaluating the clinical value with application of PCR-RDBH technique to detect EMB resistance. In the present study, the genotypes of the 258 bp fragments of embB genes from 196 clinical isolates of M. tuberculosis were analysed with RDBH and DNA sequencing. It was demonstrated that 60 out of 91 phenotypically EMB-resistant isolates (65.9%) showed 5 types of missense mutations at codon 306 of embB gene, resulting in the replacement of the Met residue of the wild type strain with Val, Ile or Leu residues. In these mutations, the GTP mutation (38/91, 41.8%) and the ATA mutation (16/91, 17.6%) were the most encountered genotypes. The embB mutation at codon 306 could also be found in 69 isolates of phenotypically EMB-sensitive but resistant to other anti-tuberculous drugs, but no such gene mutation could be found in 36 strains of drug-sensitive isolates. Meanwhile, the concordance with the results of DNA sequencing for one wide-type probe and 5 probes for specific mutations was 100% . It was concluded that the EMB-resistance occurring in most M. tuberculosis is due to appearance of embB mutation at codon 306, and the PCR-RDBH assay was proved to be a rapid, simple and reliable method for the detection of gene mutations, which might be a good alternative for the drug-resistance screening.     

Liddle's syndrome caused by a novel mutation of the γ-subunit of epithelial sodium channel gene SCNN1G in Chinese

Objective To screen the mutation of the β and γ subunits of epithelial sodium channel gene SCNN1 in two families with Liddle's syndrome. Methods Two patients clinically diagnosed as Liddle's syndrome and their family members were enrolled. Peripheral blood samples were collected and total genomic DNA was prepared. Polymerase chain reaction (PCR) was used to amplify the exon 13 of the SCNN1B and SCNN1G gene. PCR products were purified and subjected to direct DNA sequencing. Results A heterozygous nonsense mutation at codon 564 of the SCNN1B gene from CGA(Arg) to stop codon(TGA)was detector in the proband of family 1. More importantly, a novel heterozygous nonsense mutation of CAG (Gln) to stop codon TAG at codon 567 of the SCNN1G gene was detected in the proband and another two members of family 2. Conclusion Screening for specific mutations of the SCNN1 gene in relatives of patients with Liddle's syndrome can be used to identify the previously unrecognized cases within the family.A new nonsense mutation(Q567X) of the SCNN1G gene is likely the cause of Liddle's syndrome in family 2.     

Liddle's syndrome caused by a novel mutation of the γ-subunit of epithelial sodium channel gene SCNN1G in Chinese

Objective To screen the mutation of the β and γ subunits of epithelial sodium channel gene SCNN1 in two families with Liddle's syndrome. Methods Two patients clinically diagnosed as Liddle's syndrome and their family members were enrolled. Peripheral blood samples were collected and total genomic DNA was prepared. Polymerase chain reaction (PCR) was used to amplify the exon 13 of the SCNN1B and SCNN1G gene. PCR products were purified and subjected to direct DNA sequencing. Results A heterozygous nonsense mutation at codon 564 of the SCNN1B gene from CGA(Arg) to stop codon(TGA)was detector in the proband of family 1. More importantly, a novel heterozygous nonsense mutation of CAG (Gln) to stop codon TAG at codon 567 of the SCNN1G gene was detected in the proband and another two members of family 2. Conclusion Screening for specific mutations of the SCNN1 gene in relatives of patients with Liddle's syndrome can be used to identify the previously unrecognized cases within the family.A new nonsense mutation(Q567X) of the SCNN1G gene is likely the cause of Liddle's syndrome in family 2.     

特异引物双扩增即时PCR与传统测序法检测肠癌、肺癌患者K-ras基因突变的比较

Objective To map out the frequency and types of K-ras gene mutations present incolorectal and lung cancer patients; to evaluate the clinical applicability of a novel real-time double-loop probe PCR using the ADx-K-ras kit, and to compare its performance with the result by using traditional Sanger DNA sequencing in detection of somatic mutations of the tumor genes. Methods A total of 827 formalin-fixed paraffin-embedded (FFPE) blocks including 583 from the colorectal and 244 from the lung cancer patients were assayed. Genomic DNA of the sample tissues was extracted, purified and subjected to PCR amplification of K-ras gene codon 12 and 13 and DNA sequencing was carried on using both the traditional Sanger sequencing method and the ADx's K-ras mutation detection kit, respectively. The mutation rates for K-ras gene at codon 12 and 13, and the mutation frequencies detected by using both methods were analyzed. Results 533 out of 583 (91.4%) colorectal cancer samples and 144 out of 244 lung cancer samples(59.0%) were detected using the traditional Sanger DNA sequencing technique, and 583 out of 583(100.0%) colorectal plus 244 out of 244(100.0%) lung cancers were detected, respectively by using the ADx-K-ras kit. Of the 583 colorectal cancer samples, 192 (32.9%) showed mutations by using the ADx-K-ras kit in comparing with a result of 160 samples (27.4%) with K-ras gene mutation by using the traditional Sanger DNA sequencing technique. Of the 244 lung cancer samples, 26(10.7%) showed K-ras gene mutations by using ADx-K-ras kit, while in 144 samples detected by using the traditional Sanger DNA sequencing technique, only 12 samples (8.3%) showed K-ras gene mutations. In colorectal cancer analyzed, GGT→GAT at codon 12 was the most common event with 35.1% (66/188) mutations, followed by GGC→GAC at codon 13 with 26.6% (50/188) and GGT→GTT at codon 12 with 18.6% (35/188),while GGT→GCT at codon12 was the most rare with only 1.6% (3/188) of the total mutation cases. In patients with lung cancer analyzed,GGT→GTT at codon 12 was the most common mutation, accounting for 40.9% (9/22), and GGT→GCT at codon 12 the most rare with only about 4.5% (1/22) of the total mutation cases. Conclusions K-ras gene mutations were present in colorectal cases, and significantly more frequent than that in lung cancer. There were significant statistical differences between the two methods.ADx-K-ras real-time PCR showed much higher successful detection rates and mutation ratios compared to Sanger sequencing. As a result, the real-time PCR with ADx-K-ras kit proves to have a good clinical applicability and a strong advantage over the traditional Sanger DNA sequencing. It is a effective and reliable tool for clinical screening of somatic gene mutations in tumors.     

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.     

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.