title: PITX2 Loss-of-Function Mutation Contributes to Congenital Endocardial Cushion Defect and Axenfeld-Rieger Syndrome.
abstract: Congenital heart disease (CHD), the most common type of birth defect, is still the leading non-infectious cause of infant morbidity and mortality in humans. Aggregating evidence demonstrates that genetic defects are involved in the pathogenesis of CHD. However, CHD is genetically heterogeneous and the genetic components underpinning CHD in an overwhelming majority of patients remain unclear. In the present study, the coding exons and flanking introns of the PITX2 gene, which encodes a paired-like homeodomain transcription factor 2essential for cardiovascular morphogenesis as well as maxillary facial development, was sequenced in 196 unrelated patients with CHD and subsequently in the mutation carrier's family members available. As a result, a novel heterozygous PITX2 mutation, p.Q102X for PITX2a, or p.Q148X for PITX2b, or p.Q155X for PITX2c, was identified in a family with endocardial cushion defect (ECD) and Axenfeld-Rieger syndrome (ARS). Genetic analysis of the pedigree showed that the nonsense mutation co-segregated with ECD and ARS transmitted in an autosomal dominant pattern with complete penetrance. The mutation was absent in 800 control chromosomes from an ethnically matched population. Functional analysis by using a dual-luciferase reporter assay system revealed that the mutant PITX2 had no transcriptional activity and that the mutation eliminated synergistic transcriptional activation between PITX2 and NKX2.5, another transcription factor pivotal for cardiogenesis. To our knowledge, this is the first report on the association of PITX2 loss-of-function mutation with increased susceptibility to ECD and ARS. The findings provide novel insight into the molecular mechanisms underpinning ECD and ARS, suggesting the potential implications for the antenatal prophylaxis and personalized treatment of CHD and ARS.
authors.affiliation: Department of Cardiology, Tongji Hospital, Tongji University School of Medicine, Shanghai, China; Division of Medical Genetics, Tongji University School of Medicine, Shanghai, China.
authors.forename: Cui-Mei
authors.initials: CM
authors.lastname: Zhao
authors.affiliation: Division of Medical Genetics, Tongji University School of Medicine, Shanghai, China.
authors.forename: Lu-Ying
authors.initials: LY
authors.lastname: Peng
authors.affiliation: Division of Medical Genetics, Tongji University School of Medicine, Shanghai, China.
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Pediatrics, Tongji Hospital, Tongji University School of Medicine, Shanghai, China.
authors.forename: Xing-Yuan
authors.initials: XY
authors.lastname: Liu
authors.affiliation: Department of Cardiology, Tongji Hospital, Tongji University School of Medicine, Shanghai, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China.
authors.forename: Xian-Ling
authors.initials: XL
authors.lastname: Zhang
authors.affiliation: Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Yuan
authors.affiliation: Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Ruo-Gu
authors.initials: RG
authors.lastname: Li
authors.affiliation: Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Xing-Biao
authors.initials: XB
authors.lastname: Qiu
authors.affiliation: Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China; Department of Cardiovascular Research Laboratory, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China; Department of Central Laboratory, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Yi-Qing
authors.initials: YQ
authors.lastname: Yang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000869:Anterior Eye Segment / Q000002:abnormalities*; D016466:CHO Cells; D002648:Child; D002675:Child, Preschool; D002681:China; D002874:Chromosome Mapping; D015331:Cohort Studies; D003412:Cricetulus; D004694:Endocardial Cushion Defects / Q000235:genetics*; D005124:Eye Abnormalities / Q000235:genetics*; D015785:Eye Diseases, Hereditary; D005260:Female; D005838:Genotype; D006579:Heterozygote; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D010375:Pedigree; D019683:Penetrance; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics*; D015533:Transcriptional Activation; D000097577:Homeobox Protein PITX2
chemical_list: D018398:Homeodomain Proteins; D014157:Transcription Factors; D000097577:Homeobox Protein PITX2