NeuroD1 is a transcriptional activator that acts as a differentiation factor during neurogenesis. It has been demonstrated to bind to the insulin gene E-box. Efficient DNA binding requires dimerization with another basic helix-loop-helix (bHLH) protein. Defects in NEUROD1 are a cause of maturity onset diabetes of the young type VI (MODY6). MODY6 is a form of non-insulin-dependent diabetes mellitus characterized by an autosomal dominant mode of inheritance, onset during young adulthood and a primary defect in insulin secretion.