Inhibiting angiogenesis causes cell death and disrupts growth factor signalling pathways. This, in turn, causes tissue failure and the loss of chondrocytes, nerves and other cells (Vargesson, 2009). AEDs can induce teratogenicity through one or more of several mechanisms. Firstly, for instance, VPA alters expression patterns of genes important in neuronal development (e.g. homeobox genes) and neurotransmission.