Why are some children born with heart defects? Why do some families present numerous cases of heart defects? Over the last ten years, knowledge surrounding molecular cascades that regulate heart formation has increased along with the development of new genetic analysis tools for families that have many affected members. The GENCOR team has set up an important cohort comprised of families that are dealing with multiple heart defect cases, mainly left ventricular outflow tract obstructions. It studies genotypes through a SNP platform in order to conduct linkage and association analyses. It also uses CNV determination to identify new chromosomal regions responsible for these defects. These tools have allowed us to recently identify a new locus on chromosome Xq28 associated with an aortic stenosis syndrome accompanied by septal defects and atrial fibrillation. With the help of the cohort, the team will now attempt to locate the genes involved and establish genotype-phenotype correlations. This will lead to improved diagnoses and therapies for the treatment of congenital heart defects.
Another aspect of this project is aimed at identifying the epigenetic causes of these diseases. The team is studying genome methylation as well as its gene regulation to find prognosis biomarkers or potential drug alterable genetic properties.
The animal model used in our laboratory is the Xenopus laevis frog. Molecular cascades of cardiac morphogenesis are highly conserved between vertebrate species. Developmental stages such as cardiogenic field induction, linear cardiac tube formation and valve and chamber morphogenesis are similar on morphologic and molecular levels. The team chose the Xenopus laevis frog for its ease of embryological and genetic manipulations. A gene function loss or gain can be induced through a simple morpholino or RNA in a fertilized ovocyte. In this facet of the team’s research, molecular methods, confocal miscroscopy and 3D reconstructions of heart formation allow it to study signaling cascades in cardiovascular system formation.
Patient recruitment
The team is actively seeking patients for the study, especially families that have many members who suffer from heart defects. It is also recruiting families free from heart defects in order to act as a control group. Examinations include family history, medical history, a blood sample, an electrocardiogram (EKG) and an echocardiography. Interested families can contact Maryse Thibeault, Nurse Coordinator, at 514-345-4931, Extension 2789.