SP1 and psychiatric disorder: The functional role of an alternative exon 1 variant methylation in response to different types, duration and frequency of stress, as well as their relation to the risk of psychiatric disorders, suggests the existence of a site-specific methylation process at the level of NR3C1. The alternative NR3C1 first exons have different transcription factor-binding sites, e.g., 1B has consensus sequences for specificity protein 1 (SP1) [53], whereas nerve growth factor-induced protein A (EGR1) binds to 1F [54].