title: Genetic approaches to polydipsia in schizophrenia: a preliminary report of a family study and an association study of an angiotensin-converting enzyme gene polymorphism.
abstract: The pathophysiology of polydipsia in patients with schizophrenia is inadequately understood. This study aims to investigate the genetic influence on polydipsia in schizophrenia, and is comprised of a family study and an association study. First, we screened in-patients in 14 psychiatric hospitals and found a total of 36 pairs of a proband and his/her first-degree relative, both of whom were diagnosed with schizophrenia. Among these pairs, a significant familial concordance of polydipsia was found (Fisher's exact test, two-sided, P = 0.0014; odds ratio, 88.20; 95% confidence interval, 7.31-1064.34). These results indicate that genetic factors may underlie the pathophysiology of polydipsia in patients with schizophrenia. Subsequently, we examined the genetic association between polydipsia/water intoxication and the angiotensin-converting enzyme (ACE) insertion (I)/deletion (D) polymorphism in patients with chronic schizophrenia (polydipsics: n = 65; non-polydipsics: n = 97) because several lines of evidence suggested that ACE might be involved in the development of polydipsia in schizophrenia. The D allele of ACE was found to be associated with a non-significant trend toward an increased risk of polydipsia (P = 0.086). Furthermore, a significant allelic association was found between the D allele of ACE and water intoxication (P = 0.0392). This significance remained after the data were adjusted for confounding variables by regression analysis. These results suggest that the ACE D allele may be a risk factor for polydipsia/water intoxication in patients with schizophrenia.
authors.affiliation: Department of Psychiatry, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan. shinkai@med.uoeh-u.ac.jp
authors.forename: Takahiro
authors.initials: T
authors.lastname: Shinkai
authors.forename: Osamu
authors.initials: O
authors.lastname: Ohmori
authors.forename: Hiroko
authors.initials: H
authors.lastname: Hori
authors.forename: Jun
authors.initials: J
authors.lastname: Nakamura
mesh_terms: D000328:Adult; D000368:Aged; D000483:Alleles; D004326:Drinking / Q000235:genetics; D005192:Family Health; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D007703:Peptidyl-Dipeptidase A / Q000235:genetics*; D011110:Polymorphism, Genetic; D012559:Schizophrenia / Q000150:complications* / Q000235:genetics; D017384:Sequence Deletion; D014869:Water Intoxication / Q000209:etiology / Q000235:genetics*
chemical_list: D007703:Peptidyl-Dipeptidase A