However, subsequent studies have shown association of DISC1 variants with a range of different neurocognitive phenotypes and psychiatric disorders, including bipolar disorder (BPD), and major depression.
Several statistically significant single-SNP associations were observed between BPD I and variants in the PDE10A gene and between BPD II and variants in the DISC1 and GNAS genes.
Finding of alternative associating haplotypes in the same set of BPD families gives evidence for allelic heterogeneity within DISC1, eventually leading to heterogeneity in the clinical outcome as well.