Genetic mechanisms in congenital heart disease. (360G-Wellcome-078950_Z_05_Z)

We hypothesise that mutations in left-right patterning genes are responsible for a substantial proportion of human congenital heart disease that are not usually considered to be left-right patterning defects. Cited2 null mice indicate that common congenital heart disease can arise as hypomorphs or form frustes of an underlying left-right patterning defect. Human studies have recently shown that protein-coding mutations in Cited2 may account for ~2-3% of human congenital heart disease. Well-characterised patients will be recruited in collaboration with Paediatric Cardiologists at the John Radcliffe, Great Ormond St., Brompton, and St Thomas', and Royal Liverpool Hospital. They will be investigated primarily for mutations in Cited2, and also for other genes in the left-right patterning pathway (e.g. TFAP2, FoxHI, NKx2-5, Pitx2, Nodal, Cfc1) using denaturing high-performance liquid chromatography. Protein interaction and transcription co-activation assays that test the function of Cited2 in vitro have already been set up. Mutations in Cited2 will be created using site-directed mutagenesis, and will be tested in these experiments. The availability of a number of different functional point mutations of Cited2 will allow us to further understand its function at a molecular level. It will be shown that mutations in genes involved in left-right patterning cause congenital heart diseases that were not previously considered as laterality defects, and that these approaches to study can prove highly informative in understanding the function of these genes