For example, IGHMBP2 leads to differentiation defects in motoneurons and is mutated in Charcot–Marie–Tooth (CMT) 2S;73 MORC2 is a chromatin-remodeling protein regulating differentiation and mutated in CMT;74 NDRG1 promotes differentiation and is mutated in CMT4D;75 Sbf1/Sbf2 are epigenetic regulators of cell differentiation and are mutated in CMT76,77. This evidence concerns the gene IGHMBP2 and Charcot-Marie-Tooth disease type 4D.