CACNA1C and bipolar disorder: Of these loci, 3 have been implicated in bipolar disorder and schizophrenia earlier: NOTCH4 (6p21.2) with schizophrenia using a larger replication sample [13], [17], and the ITIH4 (3p21.1), and CACNA1C (12p13.3) regions, both discovered previously in the same, combined schizophrenia and bipolar disorder sample [13], [14].