Long QT syndrome is an inherited disorder of the ion channels of the cardiomyocytes. It occurs in approximately in 1:2,000 children and is associated with ventricular tachycardia, fibrillation and sudden cardiac death. The genetic defects are typically missense mutations that produce abnormal ion channels in the cell membrane. Palliative treatment in these children involves medications and intracardiac defibrillators. There is no cure for this disease that carries a lifelong risk of sudden death. Advances in biotechnology have allowed the development of induced pluripotent stem (iPS) cells and cardiomyocytes from these patients. The proposed research for this project will involve correcting of the genetic defect in these cells, with removal of the long QT phenotype from the cardiomyocytes, curing the disease at the cellular level
Aim 1. Develop iPS cell lines from children with long QT syndrome: Fibroblasts from skin biopsies obtained from children with long QT syndrome will be reprogrammed into iPS cells which will be then sub-cultured and stimulated to become cardiomyocytes. These cell lines will undergo genetic and physiologic testing to confirm the disease genotype and phenotype, as seen in the patients.
Aim 2. Genetically correct the DNA defect in the long QT cardiomyocytes: TAL Effector Nucleases (TALEN) technology will be employed to correct the mutation in genomic DNA. TALENs will be used to specifically cleave the DNA near the mutation site. The gene will be edited using a supplied donor DNA and cellular homologous recombination. These “corrected” cell lines will then undergo physiologic testing to demonstrate that the pathologic genotype and phenotype has been removed, resulting in normally functioning cardiomyocytes.