Congenital heart disease is a leading cause of death in children, exacting a substantial emotional and economic toll. To study the mechanisms of congenital heart disease, most research has sought to identify genetic mutations in human patients or to dissect cardiac developmental pathways in animal models, but the knowledge garnered has not suggested clear strategies for treatment or prevention. On the other hand, individuals who have the same mutation commonly have presentations ranging from normal to life-threatening. Such experiments of nature suggest that unknown factors modify the phenotypic expression of a mutation. If these factors were understood, they might be therapeutically mimicked to prevent or ameliorate disease in others. Our long term goal hence is to dissect the basis of incomplete penetrance and phenotypic pleiotropy. Mutation of the cardiac transcription factor NKX2-5 was one of the first among more than a dozen genes known to cause human congenital heart disease. NKX2-5 mutant phenotypes include normal hearts, simple atrial and ventricular septal defects (ASD, VSD), and complex malformations like double outlet right ventricle. To characterize the sources of phenotypic variability, we crossed inbred mouse strains to show how genetic and non-genetic factors affect the development of heart defects. Preliminary linkage analyses in the F2 intercrosses have identified multiple modifier loci for individual defects and led to a candidate VSD modifier gene. In addition, one cross replicates the commonly reported human epidemiologic association of older maternal age with an increased risk of congenital heart defects independent of any chromosomal abnormality. The maternal age effect strongly interacts with a modifier locus on chromosome 10. Thus, our guiding hypothesis is that modifier genes buffer cardiac developmental pathways against genetic and environmental insults in the majority of a population while directing the manifestation of disease in a few. Characterization of the genetic architecture of congenital heart disease in a mouse model will lead to a deeper understanding of its multifactorial basis and possibly novel strategies for prognosis and prevention.

Public Health Relevance

Congenital heart disease is a leading cause of death in children, incurring enormous emotional and economic costs on our nation. Our research seeks to understand the factors that affect whether individuals who share a common cause develop a heart defect and the particular type. Understanding how some individuals who have no or only mild disease could suggest ways to prevent heart defects in others.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL105857-05
Application #
8775688
Study Section
Genetics of Health and Disease Study Section (GHD)
Program Officer
Schramm, Charlene A
Project Start
2010-12-01
Project End
2015-11-30
Budget Start
2014-12-01
Budget End
2015-11-30
Support Year
5
Fiscal Year
2015
Total Cost
$342,000
Indirect Cost
$117,000
Name
Washington University
Department
Pediatrics
Type
Schools of Medicine
DUNS #
068552207
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
Panzer, Adam A; Regmi, Suk D; Cormier, DePorres et al. (2017) Nkx2-5 and Sarcospan genetically interact in the development of the muscular ventricular septum of the heart. Sci Rep 7:46438
Akhirome, Ehiole; Walton, Nephi A; Nogee, Julie M et al. (2017) The Complex Genetic Basis of Congenital Heart Defects. Circ J 81:629-634
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Jay, Patrick Y; Akhirome, Ehiole; Magnan, Rachel A et al. (2016) Transgenerational cardiology: One way to a baby's heart is through the mother. Mol Cell Endocrinol 435:94-102
Nogee, Julie M; Jay, Patrick Y (2016) The Heritable Basis of Congenital Heart Disease: Past, Present, and Future. Circ Cardiovasc Genet 9:315-7
Liu, Zhenyi; Brunskill, Eric; Varnum-Finney, Barbara et al. (2015) The intracellular domains of Notch1 and Notch2 are functionally equivalent during development and carcinogenesis. Development 142:2452-63
Akhirome, Ehiole; Jay, Patrick Y (2015) Rhythm genes sing more than one tune: noncanonical functions of cardiac ion channels. Circ Arrhythm Electrophysiol 8:261-2
Schulkey, Claire E; Regmi, Suk D; Magnan, Rachel A et al. (2015) The maternal-age-associated risk of congenital heart disease is modifiable. Nature 520:230-3
Prendiville, Terence; Jay, Patrick Y; Pu, William T (2014) Insights into the genetic structure of congenital heart disease from human and murine studies on monogenic disorders. Cold Spring Harb Perspect Med 4:

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