This category included several additional interesting candidate genes, including ESR1 (estrogen receptor alpha), NR2E1 (nuclear receptor subfamily 2 group E member 1), HCRTR2 (orexin receptor type 2), SYNDIG1 (synapse differentiation-inducing gene 1), DISC1 (disrupted in schizophrenia 1), and ESRRG (estrogen-related receptor gamma). Here, HCRTR2 is linked to schizophrenia.