Abstract
The tetrapeptide of cholecystokinin (CCK), CCKβ4, is known to induce panic attacks in human subjects, while CCKβ8 is reported to have a therapeutic effect on schizophrenia symptoms. Recently, we have identified a novel microsatellite polymorphism in the 5β² upstream region of the CCK gene and shown a significant association between this polymorphism and panic disorder. In this study, we have investigated the CCKβB receptor (CCKBR) gene, which is the main constituent of the CCK receptor in the CNS. Recently, a dinucleotide repeat, (CT)~n~, in the 5β² regulatory region of the CCKBR gene was reported to be associated with panic disorder in Canadian samples. To evaluate an association of the CT repeat with panic disorder and schizophrenia, we genotyped 71 subjects with panic disorder, 154 schizophrenics and 199 controls. However, no evidence of allelic association was found between the polymorphic repeat of the CCKBR gene and either panic disorder or schizophrenia (Pβ=β0.186 and 0.987, respectively). Together with the negative reports on association analyses using other polymorphisms of the CCKBR gene and Japanese samples, the present results exclude a major genetic contribution of the CCKBR gene to susceptibilities to panic disorder and schizophrenia in Japanese cohorts. Β© 2001 WileyβLiss, Inc.