Published on:
    Journal of Cardiovascular Disease Research, 2011; 2(4):206-212
    Original Article | doi:10.4103/0975-3583.89804

    Evaluating the role of connexin43 in congenital heart disease: Screening for mutations in patients with outflow tract anomalies and the analysis of knock-in mouse models


    Guo-Ying Huang1,3, Li-Jian Xie1, Kaari L. Linask2, Chen Zhang1, Xiao-Qing Zhao1,2, Yi Yang1, Guo-Min Zhou4, Ying-Jie Wu2, Lucrecia Marquez-Rosado7, Doff B. McElhinney5,8, Elizabeth Goldmuntz5, Chengyu Liu6, Paul D. Lampe7, Bishwanath Chatterjee2,9, Cecilia W. Lo2,9

    1Children’s Hospital of Fudan University,

    2Laboratory of Developmental Biology and

    3Institute of Biomedical Science of Fudan University,

    4Department of Anatomy and Histology, Shanghai Medical School of Fudan University, Shanghai, China,

    5The Children’s Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, PA,

    6Transgenic Core Facility, NIBHL/NIH, Bethesda, Maryland 20892,

    7Fred Hutchison Cancer Research Center, Seattle, WA,

    8Department of Cardiology, Children’s Hospital, Boston, MA 02115,

    9Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittshburgh, PA 15201, USA


    Background: GJA1 gene encodes a gap junction protein known as connexin 43 (Cx43). Cx43 is abundantly expressed in the ventricular myocardium and in cardiac neural crest cells. Cx43 is proposed to play an important role in human congenital heart disease, as GJA1 knock-out mice die neonatally from outflow tract obstruction. In addition, patients with visceroatrial heterotaxia or hypoplastic left heart syndrome were reported to have point mutations in GJA1 at residues that affect protein kinase phosphorylation and gating of the gap junction channel. However, as these clinical findings were not replicated in subsequent studies, the question remains about the contribution of GJA1 mutations in human congenital heart disease (CHD). Materials and Methods: We analyzed the GJA1 coding sequence in 300 patients with CHD from two clinical centers, focusing on outflow tract anomalies. This included 152 with Tetralogy of Fallot from over 200 patients exhibiting outflow tract anomalies, as well as other structural heart defects including atrioventricular septal defects and other valvar anomalies. Our sequencing analysis revealed only two silent nucleotide substitutions in 8 patients. To further assess the possible role of Cx43 in CHD, we also generated two knock-in mouse models with point mutations at serine residues subject to protein kinase C or casein kinase phosphorylation, sites that are known to regulate gating and trafficking of Cx43, respectively. Results: Both heterozygous and homozygous knock-in mice were long term viable and did not exhibit overt CHD. Conclusion: The combined clinical and knock-in mouse mutant studies indicate GJA1 mutation is not likely a major contributor to CHD, especially those involving outflow tract anomalies.

    Key words: Connexin43, congenital heart disease, gap junction, knock-in mouse model, outflow tract, phosphorylations.