This 2 bp deletion form of CHRFAM7A is an even stronger inhibitor of α7 nAChR than wild-type CHRFAM7A and consistent with this, several studies support an association of the 2 bp deletion in the CHRFAM7A gene with schizophrenia and bipolar disorder (summarized by Sinkus et al. [150]). Here, CHRFAM7A is linked to bipolar disorder.