CACNA1C and bipolar disorder: We were interested in this question because 1) variants in this gene have been associated with psychiatric disease, especially bipolar disorder and schizophrenia, 2) bipolar disorder and schizophrenia are associated with various sleep disturbances, 3) the Cacna1c channel has been implicated in sleep-wake regulation, and 4) there are strong genetic influences for sleep consolidation in infancy.