Association studies of the CT repeat polymorphism in the 5 ' upstream region of the cholecystokinin B receptor gene with panic disorder and schizophrenia in Japanese subjects

The tetrapeptide of cholecystokinin (CCK), CCK-4, is known to induce panic attacks in human subjects, while CCK-8 is reported to have a therapeutic ef fect on schizophrenia symptoms. Recently, we have identified a novel micros atellite polymorphism in the 5' upstream region of the CCK gene and shown a significant association between this polymorphism and panic disorder. In t his study, we have investigated the CCK-B receptor (CCKBR) gene, which is t he main constituent of the CCK receptor in the CNS. Recently, a dinucleotid e repeat, (CT)(n), in the 5' regulatory region of the CCKBR gene was report ed to be associated with panic disorder in Canadian samples. To evaluate an association of the CT repeat with panic disorder and schizophrenia, we gen otyped 71 subjects with panic disorder, 154 schizophrenics and 199 controls . However, no evidence of allelic association was found between the polymor phic repeat of the CCKBR gene and either panic disorder or schizophrenia (P =0.186 and 0.987, respectively). Together with the negative reports on asso ciation analyses using other polymorphisms of the CCKBR gene and Japanese s amples, the present results exclude a major genetic contribution of the CCK BR gene to susceptibilities to panic disorder and schizophrenia in Japanese cohorts. (C) 2001 Wiley-Liss, Inc.