COMT and alexithymia: From these studies, the candidate genes associated with alexithymia risk were solute carrier family 6 member 4 (SLC6A4), serotonin 1A receptor (HTR1A), serotonin 1A receptor (HTR2A), dopamine receptor D2 (DRD2), ankyrin repeat and kinase domain containing 1 (ANKK1), catechol-o-methyltransferase (COMT), brain-derived neurotrophic factor (BDNF), oxytocin receptor (OXTR), vitamin D-binding protein (VDBP), tumor protein P53 regulated apoptosis inducing protein 1 (TP53AIP1), Rho GTPase Activating Protein 32 (ARHGAP32) and transmembrane protein 88B (TMEM88B).