Showing papers by "Joanne M. Meyer published in 2003"
TL;DR: This study provides further evidence for the hypothesis that the DISC1 gene is involved in the aetiology of schizophrenia, and implies a putative sex difference for the effect of the gene.
Abstract: We have previously reported a linkage peak on 1q42 in a Finnish schizophrenia sample. In this study we genotyped 28 single nucleotide polymorphisms (SNPs) from 1q42 covering the three candidate genes TRAX, DISC1 and DISC2, using a study sample of 458 Finnish families ascertained for schizophrenia. Two-point and haplotype association analysis revealed a significant region of interest within the DISC1 gene. A common haplotype (HEP3) was observed to be significantly under-transmitted to affected individuals (P ¼ 0.0031). HEP3 represents a two SNP haplotype spanning from intron 1 to exon 2 of DISC1. This haplotype also displayed sex differences in transmission distortion, the under-transmission being significant only to affected females (P ¼ 0.00024). Three other regions of interest were observed in the TRAX and DISC genes. However, analysis of only those families with complete genotype information specifically highlights the HEP3 haplotype as a true observation. The finding of a common under-transmitted SNP haplotype might imply that this particular allele offers some protection from the development of schizophrenia. Analysis of componenttraits of schizophrenia, derived from the Operational Criteria Checklist of Psychotic Illness (OCCPI), displayed association of HEP3 to features of the general phenotype of schizophrenia, including traits representing delusions, hallucinations and negative symptoms. This study provides further evidence for the hypothesis that the DISC1 gene is involved in the aetiology of schizophrenia, and implies a putative sex difference for the effect of the gene. Our findings would also encourage more detailed analyses of the effect of DISC1 on the component-traits of schizophrenia.
340 citations
TL;DR: The results demonstrate the complexity of the concept of 'detectable LD' and emphasize the importance of understanding population history when designing a strategy for disease gene mapping.
Abstract: Linkage disequilibrium (LD) has been an efficient tool for fine mapping of monogenic disease genes in population isolates. Its usefulness for identification of predisposing loci for common, polygenic diseases has been challenged on the basis of anticipated allelic and locus heterogeneity. We compared the extent of LD among marker loci in Finnish subpopulations with divergent but well-characterized histories. One study sample represents the early settlement Finnish population, descended from two immigration events 4,000 and 2,000 years ago. The second sample represents the geographically large late settlement region, populated 15 generations ago by several small immigrant groups from the early settlement region. The third is a restricted regional subpopulation in northeastern Finland which was founded 12 generations ago by 39 immigrant families from the late settlement region. We genotyped 243 microsatellite markers and 68 single nucleotide polymorphisms (SNPs) on chromosomes 1q and 5q. The genealogy of the families from the early (n=16) and late settlements (n=54) and the isolated settlement (n=54) was studied in detail back to the 1800s. Microsatellite data revealed greater LD in the young, founder subpopulation than was seen in either of the older populations. Observed linkage disequilibrium correlated not only with physical distance between markers but also with the information content of the markers. Using biallelic SNP markers, significant LD could only be detected up to 0.1 cM. Our results demonstrate the complexity of the concept of 'detectable LD' and emphasize the importance of understanding population history when designing a strategy for disease gene mapping.
146 citations
TL;DR: The results propose several new candidate genes for the metabolic syndrome and suggest that the genetic basis of this syndrome may be strongly modified by gender.
Abstract: Major genetic determinants of the metabolic syndrome — a clustering of abdominal obesity, high triglycerides, low HDL cholesterol, high blood pressure and high fasting glucose — remain elusive. We surveyed 207 single-nucleotide polymorphisms in 110 candidate genes among coronary artery disease patients, a population enriched for metabolic abnormalities. The number of abnormalities (0–5) was determined in the 214 male and 91 female patients, and the association with each polymorphism evaluated by means of ordinal regression analysis. Polymorphisms in eight genes, including LDLR, GBE1, IL1R1, TGFB1, IL6, COL5A2, SELE and LIPC, were associated with metabolic syndrome in the whole population (P values ranged from 0.047 to 0.008). Variants in seven additional genes showed significant gene by gender interaction. Among these, separate analyses in men and women revealed a strong association with a silent polymorphism in the low-density lipoprotein receptor-related protein gene, LRPAP1, among females (P=0.0003), but not males (P=0.292). Other genes associated only in females included THBS1, ACAT2, ITGB3, F2 and SELP (P values ranging from 0.032 to 0.002). Only one gene (PRCP) was significantly associated in men alone (P=0.039). Our results propose several new candidate genes for the metabolic syndrome and suggest that the genetic basis of this syndrome may be strongly modified by gender.
107 citations
TL;DR: Genotype combinations for the three polymorphisms in linkage disequilibrium (IVS5, EX8 and IVS10) were found to be associated with HDL-C among women from the Israeli and Swedish populations, and one specific pattern of genotypes was consistently associated with the lowest mean levels of LDL-C in women from all three populations.
Abstract: Objective: We examined polymorphisms in the HDL receptor, SR-BI, for association with plasma HDL cholesterol levels. Methods: Study subjects, including 847 women and 725 men, were from families originally ascertained for type 2 diabetes from Finland, Sweden and Israel. Four common polymorphisms were examined in linear regression analysis: an exon 1 missense (EX1), exon 8 silent (EX8), intron 5 (IVS5) and intron 10 (IVS10) variants. Results: Genotype combinations for the three polymorphisms in linkage disequilibrium (IVS5, EX8 and IVS10) were found to be associated with HDL-C among women from the Israeli (p = 0.01) and Swedish (p = 0.06) populations. In Finnish women, the association was only apparent after taking into account effect modification by triglyceride levels (p = 0.04). One specific pattern of genotypes, denoted by presence of the IVS5_T and EX8_C alleles, and absence of the IVS10_G allele, was consistently associated with the lowest mean levels of HDL-C in women from all three populations. These same associations were not found in men. Conclusions: Polymorphic variation of the SR-BI gene may influence HDL-C levels and act in a sex-dependent manner. Copyright (C) 2003 S. Karger AG, Basel.
32 citations