Objective： Axenfeld-Rieger syndrome （ARS） is phenotypically and genetically heterogeneous. In this study we identified the underlying genetic defect in a Chinese family with ARS. Methods： A detailed family history...Objective： Axenfeld-Rieger syndrome （ARS） is phenotypically and genetically heterogeneous. In this study we identified the underlying genetic defect in a Chinese family with ARS. Methods： A detailed family history and clinical data were recorded. The ocular phenotype was documented using slit-lamp photography and systemic anomalies were also documented where available. The genomic DNA was extracted from peripheral blood leukocytes. All coding exons and intron-exon junctions of paired-like homeodomain transcription factor 2 （PITX2） gene and the forkhead box C1 （FOXC1） gene were amplified by polymerase chain reaction （PCR） and screened for mutation by direct DNA sequencing. Variations detected in exon 5 of PITX2 were further evaluated with cloning sequencing. The exon 5 of PITX2 was also sequenced in 100 healthy controls, unrelated to the family, for comparison. Structural models of the wild type and mutant homeodomain of PITX2 were investigated by SWISS-MODEL. Results： Affected individuals exhibited variable ocular phenotypes, whereas the systemic anomalies were similar. After direct sequencing and cloning sequencing, a heterozygous deletion/insertion mutation c. 198_201delinsTTTCT （p.M661fs＊133） was revealed in exon 5 of PITX2. This mutation co-segregated with all affected individuals in the family and was not found either in unaffected family members or in 100 unrelated controls. Conclusions： We detected a novel frameshift mutation p.M661fs＊133 in PITX2 in a Chinese family with ARS. Although PITX2 mutations and polymorphisms have been re- ported from various ethnic groups, we report for the first time the identification of a novel deletion/insertion mutation that causes frameshift mutation in the homeodomain of PITX2 protein.展开更多
The bicoid-related transcription factor 2(Pitx2)plays a crucial role in the development of many organs and tissues by affecting the mitotic cell cycle.Postnatal testis development is related to mitosis and meiosis in ...The bicoid-related transcription factor 2(Pitx2)plays a crucial role in the development of many organs and tissues by affecting the mitotic cell cycle.Postnatal testis development is related to mitosis and meiosis in mul-tiple cell types,but the role of Pitx2 gene in seasonal inhibition of testicular development remains unknown in rodents.We analyzed PITX2 protein and Pitx2 mRNA expression features using both laboratory and wild male Rattus norvegicus caraco.In postnatal testicle of laboratory colony,we found that PITX2 was expressed in Leydig cells,pachytene spermatocytes,round spermatids,and elongating spermatids rather than spermatogonia and lep-totene/zygotene spermatocytes.Pitx2b expression significantly increased along with the occurrence of pachytene spermatocytes and round spermatids,while decreased along with the processes of elongated spermatids.In wild male rats with similar testes weight,a significantly suppressed Pitx2b expression occurred with an active meiotic stage in the inhibited testes in autumn and winter,compared with the normally developing testes in spring and summer.These results indicate that Pitx2b expression suppression plays a crucial role in the seasonal inhibition of testis development.展开更多
AIM: To study clinical features and gene mutations within the paired-like homeodomain transcription factor 2 (PITX2) gene in a pedigree of bilateral limbal dermoids. METHODS: Complete eye examinations have been perfor...AIM: To study clinical features and gene mutations within the paired-like homeodomain transcription factor 2 (PITX2) gene in a pedigree of bilateral limbal dermoids. METHODS: Complete eye examinations have been performed on each individual of the family. Exons of paired-like homeodomain transcription factor 2 ( PITX2)were amplified by polymerase chain reaction, sequenced, and compared with a reference database. RESULTS: We described the phenotype, clinic findings in a family with two affected members. The masses of the proband's eyes were excised surgically demonstrating a dermoid cyst by histopathological examination. No mutation was detected in the gene PITX2 in this pedigree. CONCLUSION: A family of limbal dermoid cyst was reported. In addition, no pathogenic sequence variations were found in PITX2, indicating that this phenotype in this family is a distinctive entity.展开更多
AIM： To describe a Chinese family affected by a severe form of Axenfeld-Rieger syndrome （ARS） and characterize the molecular defect in PITX2 in the family. METHODS： Patients presented with typical ARS from a Chin...AIM： To describe a Chinese family affected by a severe form of Axenfeld-Rieger syndrome （ARS） and characterize the molecular defect in PITX2 in the family. METHODS： Patients presented with typical ARS from a Chinese family were investigated. We performed genome- wide linkage scan and exome sequencing to identify the pathogenic mutations, Candidate mutations were verified for co-segregation in the whole pedigree using Sanger sequencing, Real-time polymerase chain reaction （RT- PCR） and Western blotting were performed to verify the expression of the pathogenic gene. RESULTS： Genome-wide linkage and exome sequencing analyses showed PITX2 as the disease candidate gene. A〉G substitution at position -11 of 3＇ss of exon 5 （IVS5- 11A〉G） that co-segregated with the disease phenotype was discovered in the family. The PITX2 messenger ribonucleic acid and protein levels were about 50% lower in patients with ARS than in unaffected family members in the family, CONCLUSION： Our findings implicate the first intronic mutation of the PITX2 gene in the pathogenesis of a severe form of ARS in a Chinese family. This study highlights the importance of a systematic search for intronic mutation in ARS cases for which no mutations in the exons of PITX2 have been found.展开更多
基金Project supported by the Qianjiang Talents Project of Zhejiang Province(No.2010R10067)the Zhejiang Key Innovation Team Project of China(No.2009R50039)the Zhejiang Key Laboratory Foundation of China(No.2011E10006)
文摘Objective： Axenfeld-Rieger syndrome （ARS） is phenotypically and genetically heterogeneous. In this study we identified the underlying genetic defect in a Chinese family with ARS. Methods： A detailed family history and clinical data were recorded. The ocular phenotype was documented using slit-lamp photography and systemic anomalies were also documented where available. The genomic DNA was extracted from peripheral blood leukocytes. All coding exons and intron-exon junctions of paired-like homeodomain transcription factor 2 （PITX2） gene and the forkhead box C1 （FOXC1） gene were amplified by polymerase chain reaction （PCR） and screened for mutation by direct DNA sequencing. Variations detected in exon 5 of PITX2 were further evaluated with cloning sequencing. The exon 5 of PITX2 was also sequenced in 100 healthy controls, unrelated to the family, for comparison. Structural models of the wild type and mutant homeodomain of PITX2 were investigated by SWISS-MODEL. Results： Affected individuals exhibited variable ocular phenotypes, whereas the systemic anomalies were similar. After direct sequencing and cloning sequencing, a heterozygous deletion/insertion mutation c. 198_201delinsTTTCT （p.M661fs＊133） was revealed in exon 5 of PITX2. This mutation co-segregated with all affected individuals in the family and was not found either in unaffected family members or in 100 unrelated controls. Conclusions： We detected a novel frameshift mutation p.M661fs＊133 in PITX2 in a Chinese family with ARS. Although PITX2 mutations and polymorphisms have been re- ported from various ethnic groups, we report for the first time the identification of a novel deletion/insertion mutation that causes frameshift mutation in the homeodomain of PITX2 protein.
基金supported by the National Nature Science Foundation of China(grant numbers 31972285,32090022,and 31000858).
文摘The bicoid-related transcription factor 2(Pitx2)plays a crucial role in the development of many organs and tissues by affecting the mitotic cell cycle.Postnatal testis development is related to mitosis and meiosis in mul-tiple cell types,but the role of Pitx2 gene in seasonal inhibition of testicular development remains unknown in rodents.We analyzed PITX2 protein and Pitx2 mRNA expression features using both laboratory and wild male Rattus norvegicus caraco.In postnatal testicle of laboratory colony,we found that PITX2 was expressed in Leydig cells,pachytene spermatocytes,round spermatids,and elongating spermatids rather than spermatogonia and lep-totene/zygotene spermatocytes.Pitx2b expression significantly increased along with the occurrence of pachytene spermatocytes and round spermatids,while decreased along with the processes of elongated spermatids.In wild male rats with similar testes weight,a significantly suppressed Pitx2b expression occurred with an active meiotic stage in the inhibited testes in autumn and winter,compared with the normally developing testes in spring and summer.These results indicate that Pitx2b expression suppression plays a crucial role in the seasonal inhibition of testis development.
文摘AIM: To study clinical features and gene mutations within the paired-like homeodomain transcription factor 2 (PITX2) gene in a pedigree of bilateral limbal dermoids. METHODS: Complete eye examinations have been performed on each individual of the family. Exons of paired-like homeodomain transcription factor 2 ( PITX2)were amplified by polymerase chain reaction, sequenced, and compared with a reference database. RESULTS: We described the phenotype, clinic findings in a family with two affected members. The masses of the proband's eyes were excised surgically demonstrating a dermoid cyst by histopathological examination. No mutation was detected in the gene PITX2 in this pedigree. CONCLUSION: A family of limbal dermoid cyst was reported. In addition, no pathogenic sequence variations were found in PITX2, indicating that this phenotype in this family is a distinctive entity.
基金Supported by China Postdoctoral Science Foundation Funded Project(No.2017M612211)the National Natural Science Foundation of China(No.81300742+2 种基金No.81600721)the Shandong Province Medical and Health Technology Development Project(No.2016WS0265)the Science and Technology Plan of Qingdao(No.15-9-1-35-jch)
文摘AIM： To describe a Chinese family affected by a severe form of Axenfeld-Rieger syndrome （ARS） and characterize the molecular defect in PITX2 in the family. METHODS： Patients presented with typical ARS from a Chinese family were investigated. We performed genome- wide linkage scan and exome sequencing to identify the pathogenic mutations, Candidate mutations were verified for co-segregation in the whole pedigree using Sanger sequencing, Real-time polymerase chain reaction （RT- PCR） and Western blotting were performed to verify the expression of the pathogenic gene. RESULTS： Genome-wide linkage and exome sequencing analyses showed PITX2 as the disease candidate gene. A〉G substitution at position -11 of 3＇ss of exon 5 （IVS5- 11A〉G） that co-segregated with the disease phenotype was discovered in the family. The PITX2 messenger ribonucleic acid and protein levels were about 50% lower in patients with ARS than in unaffected family members in the family, CONCLUSION： Our findings implicate the first intronic mutation of the PITX2 gene in the pathogenesis of a severe form of ARS in a Chinese family. This study highlights the importance of a systematic search for intronic mutation in ARS cases for which no mutations in the exons of PITX2 have been found.
