What gene does bipolar disorder happen in?

There is no single gene that causes bipolar disorder, but rather a complex interaction of multiple genes and environmental factors. Genetic studies have identified several variations in different genes that may increase the risk of developing bipolar disorder, but these variations are not deterministic and their effects are often small. Some of the genes that have been implicated in bipolar disorder include those involved in neurotransmission, neural development, and cellular signalling. However, much more research is needed to fully understand the genetic basis of bipolar disorder.