Abstract
Several lines of research indicate a cholecystokinin (CCK) deficit in schizophrenia patients. A C to T substitution was found in the promoter region of the CCK gene. We investigated this promoter variant in patients with schizophrenia and geographicallyβmatchedcontrols. The T allele was detected in 24% of the 85 schizophrenics and 16% of the 247 controls. No significant difference in the T allele frequency was found between patients and controls (Ο^2^β=β2.77, Pβ>β0.1). The schizophrenia sample was analyzed further along the dimensions of positive and negative symptoms. The patients with prominent negative symptoms presented a statistically significant association to the T allele (Ο^2^β=β4.13, Pβ<β0.04). However, the significance disappeared after the Bonferroni correction (Pβ>β0.15). Since the caseβcontrol analysis may present incorrect ethnic match between cases and controls, we applied the familyβbased tests to verify the above findings. Both transmission disequilibrium test (TDT; Ο^2^β=β5.33, Pβ<β0.025 in 12 trios) and haplotype relative risk (HRR; Ο^2^β=β3.844, Pβ<β0.05 in 60 trios) indicated a significantly high transmission of T allele to schizophrenia offspring probands from their parents. While our familyβbased tests seem to support the CCK involvement in schizophrenia, no definite conclusion can be drawn based on such a small sample size. This preliminary finding is subjected to future investigations. Β© 2002 WileyβLiss, Inc.