 The derivation of human iPS cells 1-5 open new avenues to model human diseases since it may now be possible to develop iPS cells from the fibroblasts or other somatic cells of patients with various conditions. These iPS cells may be directed to differentiate into the cells which are affected in specific conditions. Abnormalities in the development of the affected cells as well as altered survival or function of the cells may be studied. Thus iPS cells may serve as an invaluable model for the study of the pathogenesis of human diseases and may also serve for the development of new drugs, and high throughput screening of molecules for toxic or therapeutic effects. 