ABSTRACT
BACKGROUND:Some studies have shown that more copy number variations are present in early passage human induced pluripotent stem cells than later passage human human induced pluripotent stem cells, their parental somatic fibroblasts or human embryonic stem cells. OBJECTIVE:To investigate whether the reprogramming process itself compromises genomic stability and further explore the efficiency of induced pluripotent stem cellestablishment. METHODS:Using high-resolution Affymetrix CytoScan HD array, we compared copy number variations and loss of heterozygosity in early passage induced pluripotent stem cells with their fibroblast cellorigins from genetic epilepsy patients. RESULTS AND CONCLUSION:Compared with somatic fibroblasts from genetic epilepsy patient, there was no difference in the loss of heterozygosity between the two types of cells, but more copy number variations were present in early passage human induced pluripotent stem cells which were characterized as microduplication and involved oncogenic genes. Results demonstrate the dynamic nature of genomic abnormalities during reprogramming process and the necessity of frequent monitoring human induced pluripotent stem cells to assure their genomic stability and clinical safety.