Study Report

Reference	Vincent, J. B.,1999(b) PMID: 10395212
Citation	Vincent, J. B., A. Petronis, et al. (1999). "Analysis of genome-wide CAG/CTG repeats, and at SEF2-1B and ERDA1 in schizophrenia and bipolar affective disorder." Mol Psychiatry 4(3): 229-234.
Disease Type	Bipolar Disorder & Schizophrenia
Study Design	case-control
Study Type	Candidate-gene association study
Sample Size	Over 100 patients with bipolar affective disorder and their matched comparison subjects
SNP/Region/Marker Size	2 variants
Predominant Ethnicity	Caucasian
Population	Canadian
Gender	Fifty-seven per cent were female and 43% were male for BPAD study. Twenty-eight percent were female and 72% were male for SZ study.
Age Group	Adults : Mean age for BPAD was 39.0,SD = 10.7 years, and for the matched controls 38.0,SD = 10.2 years. Mean age for SCZ was 34.2,SD = 8.5 years, and for the matched controls 33.3,SD = 8.3 years.

Sample Diagnosis	RDC
Sample Status	Individuals with bipolar affective disorder were recruited from the Bipolar Clinic at The Clarke Institute of Psychiatry, Toronto. They met the Research Diagnostic Criteria for bipolar affective disorder as determined by interview with the Schedule for Affective Disorders and Schizophrenia-Lifetime Version. All of the bipolar subjects (N = 103) were classified as having bipolar affective disorder, type I. The comparison subjects were recruited from staff members at Case Western Reserve University, Cleveland, and the local community around The Clarke Institute and had no history of major psychiatric illness. They were closely matched pairwise to the unrelated bipolar subjects in age (± 5 years), sex, and detailed ethnic background, including preimmigration roots.95% were Caucasian, 3% Oriental, and 2% Native Canadian. All individuals in the comparison group were above the median age at onset for bipolar affective disorder (18 years for males, 20 years for females) and thus had largely passed through the age of risk for developing the disorder.
Technique	Genotyping
Statistical Method	chi-square tests (SPSS 7.0, Chicago)
Result Summary	Alleles at two recently discovered unstable trinucleotide repeat loci at 18q21.1 (SEF2-1B) and 17q21.3 (ERDA1) have also been analysed in affecteds and matched controls. We observed no increase in frequency of larger alleles (>37 repeats) in affected individuals at SEF2-1B (BPAD: P=0.95, n= 100; SCZ: P=0.61, n=97) or at ERDA1 (BPAD: P= 0.4, n = 101; SCZ: P= 0.05, n = 151, with larger alleles more frequent in controls). Our findings suggest that larger CAG/CTG repeats at these loci are neither major contributory factors to the etiology of psychosis, nor in linkage disequilibrium with a gene that is. Furthermore, when the RED results were compared to allele sizes at SEF2-1B and ERDA1, it was observed that a majority of SCZ, BPAD and control individuals with large RED products had a large allele at either or both sites (78% for RED products > or =270 bp; 62% for RED products > or =180 bp).