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
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
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.
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.
