or other type of somatic cells from a different type of somatic cells, such as fibroblasts. As an advantage of direct conversion, authentic human neurons that reflect important aspects of cellular aging can be generated50. However, the non-renewable source of cells provided by this approach may not be applicable for large-scale drug screening. The forced expression of transcription factors also offers the potential to differentiate patient iPSCs much more rapidly. In a recent study, forced expression of MYOD1 (myogenic differentiation gene), a master regulator of skeletal muscle differentiation, was used to produce new cellular models of intractable muscle disease pathologies such as Miyoshi myopathy133 and Duchenne-type muscular dystrophy134.
