BMI-associated alleles do not constitute risk alleles for polycystic ovary syndrome independently of BMI: a case-control study.

Introduction: Polycystic Ovary Syndrome (PCOS) has a strong genetic background and the majority of patients with PCOS have elevated BMI levels. The aim of this study was to determine to which extent BMI-increasing alleles contribute to risk of PCOS when contemporaneous BMI is taken into consideration.

Methods: Patients with PCOS and controls were recruited from the United Kingdom (563 cases and 791 controls) and The Netherlands (510 cases and 2720 controls).

MicroRNA expression in abdominal and gluteal adipose tissue is associated with mRNA expression levels and partly genetically driven.

To understand how miRNAs contribute to the molecular phenotype of adipose tissues and related traits, we performed global miRNA expression profiling in subcutaneous abdominal and gluteal adipose tissue of 70 human subjects and characterised which miRNAs were differentially expressed between these tissues. We found that 12% of the miRNAs were significantly differentially expressed between abdominal and gluteal adipose tissue (FDR adjusted p<0.05) in the primary study, of which 59 replicated in a follow-up study of 40 additional subjects.

Genetics and epigenetics of obesity.

Obesity results from interactions between environmental and genetic factors. Despite a relatively high heritability of common, non-syndromic obesity (40-70%), the search for genetic variants contributing to susceptibility has been a challenging task. Genome wide association (GWA) studies have dramatically changed the pace of detection of common genetic susceptibility variants.

The genetics of obesity.

Obesity is a result of excess body fat accumulation. This excess is associated with adverse health effects such as CVD, type 2 diabetes, and cancer. The development of obesity has an evident environmental contribution, but as shown by heritability estimates of 40% to 70%, a genetic susceptibility component is also needed.

Parent-of-origin effects at the major histocompatibility complex in multiple sclerosis.

Multiple sclerosis (MS) susceptibility is characterized by maternal parent-of-origin effects and increased female penetrance. In 7796 individuals from 1797 MS families (affected individuals n = 2954), we further implicate epigenetic modifications within major histocompatibility complex (MHC) class II haplotypes as mediating these phenomena. Affected individuals with the main MS-associated allele HLA-DRB1*15 had a higher female-to-male ratio versus those lacking it (P = 0.

MicroRNA-125a is over-expressed in insulin target tissues in a spontaneous rat model of Type 2 Diabetes.

Background: MicroRNAs (miRNAs) are non-coding RNA molecules involved in post-transcriptional control of gene expression of a wide number of genes, including those involved in glucose homeostasis. Type 2 diabetes (T2D) is characterized by hyperglycaemia and defects in insulin secretion and action at target tissues. We sought to establish differences in global miRNA expression in two insulin-target tissues from inbred rats of spontaneously diabetic and normoglycaemic strains.

Epistasis among HLA-DRB1, HLA-DQA1, and HLA-DQB1 loci determines multiple sclerosis susceptibility.

Multiple sclerosis (MS), a common central nervous system inflammatory disease, has a major heritable component. Susceptibility is associated with the MHC class II region, especially HLA-DRB5*0101-HLA-DRB1*1501-HLA-DQA1*0102-HLA-DQB1*0602 haplotypes(hereafter DR2), which dominate genetic contribution to MS risk. Marked linkage disequilibrium (LD) among these loci makes identification of a specific locus difficult.

Expression of the multiple sclerosis-associated MHC class II Allele HLA-DRB1*1501 is regulated by vitamin D.

Multiple sclerosis (MS) is a complex trait in which allelic variation in the MHC class II region exerts the single strongest effect on genetic risk. Epidemiological data in MS provide strong evidence that environmental factors act at a population level to influence the unusual geographical distribution of this disease. Growing evidence implicates sunlight or vitamin D as a key environmental factor in aetiology.

Epigenetics in multiple sclerosis susceptibility: difference in transgenerational risk localizes to the major histocompatibility complex.

Multiple sclerosis (MS) susceptibility demonstrates a complex pattern of inheritance. Haplotypes containing HLA-DRB1*1501 carry most of the genetic risk. Epidemiological evidence implicating epigenetic factors includes complex distortion of disease transmission seen in aunt/uncle-niece/nephew (AUNN) pairs.

No effect of birth weight on the risk of multiple sclerosis. A population-based study.

Background: Genetic and environmental factors have important roles in multiple sclerosis (MS) susceptibility. A clear maternal effect has been shown in several population-based studies. This parent-of-origin effect could result from factors operating during gestation.

HLA class I alleles tag HLA-DRB1*1501 haplotypes for differential risk in multiple sclerosis susceptibility.

The major locus for multiple sclerosis (MS) susceptibility is located within the class II region of the Major Histocompatibility Complex (MHC). HLA-DRB1 alleles, constituting the strongest MS susceptibility factors, have been widely exploited in research including construction of transgenic animal models of MS. Many studies have concluded that HLA-DRB1*15 allele itself determines MS-associated susceptibility.

Evidence for genetic regulation of vitamin D status in twins with multiple sclerosis.

Background: Multiple sclerosis (MS) risk is determined by both genes and environment. One of the most striking features of MS is its geographic distribution, particularly the pattern of high MS frequency in areas with low sunlight exposure, the main inducer of vitamin D synthesis. Recent epidemiologic, experimental, and clinical evidence support an effect for low environmental supplies of vitamin D in mediating an increased susceptibility to MS.

Methylation of class II transactivator gene promoter IV is not associated with susceptibility to multiple sclerosis.

Background: Multiple sclerosis (MS) is a complex trait in which alleles at or near the class II loci HLA-DRB1 and HLA-DQB1 contribute significantly to genetic risk. The MHC class II transactivator (MHC2TA) is the master controller of expression of class II genes, and methylation of the promoter of this gene has been previously been shown to alter its function. In this study we sought to assess whether or not methylation of the MHC2TA promoter pIV could contribute to MS disease aetiology.

Analysis of 45 candidate genes for disease modifying activity in multiple sclerosis.

Multiple sclerosis (MS) is a common inflammatory disease of the central nervous system unsurpassed for its variability in disease outcome. As little is conclusively known about MS disease mechanisms, we have selected a variety of candidate genes that may influence the prognosis of the disease based on their function. A cohort of sporadic MS cases, taken from opposite extremes of the putative distribution of long-term outcome using the most stringent clinical criteria to date, was used to determine the role of on MS disease severity.

Parental non-inherited HLA resistance alleles do not confer protection against multiple sclerosis.

Multiple sclerosis (MS) is a complex trait in which alleles at or near the class II loci HLA-DRB1 and HLA-DQB1 contribute significantly to genetic risk. HLA-DRB1*14 and DRB1*11 bearing haplotypes protect against MS and DRB1*01 and DRB1*10 interact with DRB1*15 to reduce risk of the disease. Recent work in other autoimmune diseases such as rheumatoid arthritis has suggested that maternal non-transmitted protective alleles can also confer disease resistance.

A first stage genome-wide screen for regions shared identical-by-descent in Hutterite families with multiple sclerosis.

The complexity of multiple sclerosis (MS) genetics has made the search for novel genes using traditional sharing methods problematic. In order to minimize the genetic heterogeneity present in the MS population we have screened the Canadian MS population for individuals belonging to the Hutterite Brethren. Seven Hutterites with clinically definite MS were ascertained and are related to a common founder by eight generations.

A genome-wide scan in forty large pedigrees with multiple sclerosis.

The epidemiology of multiple sclerosis suggests that a complex interaction of genes and environment contribute to susceptibility. To enrich for families with large genetic effects and to potentially reduce genetic heterogeneity, we screened a sample of 18,794 probands and identified forty families with four or more affected individuals. Within these 40 families, HLA DRB1*15 was present in 70% of affected individuals; the transmission disequilibrium test showed a significant excess in transmission of DRB1*15 alleles to affected individuals (47 transmitted, 19 untransmitted, chi (2) = 11.

Parental transmission of HLA-DRB1*15 in multiple sclerosis.

Multiple sclerosis (MS) is a complex trait in which HLA-DRB1*15 bearing MHC haplotypes increase risk of MS in people of Northern European descent. In this investigation of 7,334 individuals from 1,515 MS families, the largest cohort used to study the HLA-DRB1 locus to date, we analysed the transmission of HLA-DRB1*15 haplotypes stratified by sex of transmitting parent. A significant over transmission of HLA-DRB1*15 from mothers was observed (chi (2) = 7.

The inheritance of resistance alleles in multiple sclerosis.

Multiple sclerosis (MS) is a complex trait in which alleles at or near the class II loci HLA-DRB1 and HLA-DQB1 contribute significantly to genetic risk. HLA-DRB1*15 and HLA-DRB1*17-bearing haplotypes and interactions at the HLA-DRB1 locus increase risk of MS but it has taken large samples to identify resistance HLA-DRB1 alleles. In this investigation of 7,093 individuals from 1,432 MS families, we have assessed the validity, mode of inheritance, associated genotypes, and the interactions of HLA-DRB1 resistance alleles.

Transmission of class I/II multi-locus MHC haplotypes and multiple sclerosis susceptibility: accounting for linkage disequilibrium.

The human major histocompatibility complex (MHC) class II region is associated with genetic susceptibility to multiple sclerosis (MS). Roles for HLA class I loci have been supported in several case-control studies, but this methodology does not consider the known linkage disequilibrium (LD) between class I and II loci. In 1258 individuals from 294 MS families, we analysed class I and II interactions.

Autoimmune disease in families with multiple sclerosis: a population-based study.

Background: Evidence of an association between multiple sclerosis (MS) and other autoimmune diseases would substantiate the hypothesis that MS is an autoimmune disease, and implicate a common mechanism. We aimed to investigate and compare the rate of autoimmune disease in MS patients, in their first-degree relatives, and in their unrelated spouses.

Methods: We used data from a national, multicentre, population-based sample to investigate the rate of autoimmune disease in 5031 MS patients, 30 259 of their first-degree relatives, and 2707 spousal controls.

Sex ratio of multiple sclerosis in Canada: a longitudinal study.

Background: Incidence of multiple sclerosis is thought to be increasing, but this notion has been difficult to substantiate. In a longitudinal population-based dataset of patients with multiple sclerosis obtained over more than three decades, we did not show a difference in time to diagnosis by sex. We reasoned that if a sex-specific change in incidence was occurring, the female to male sex ratio would serve as a surrogate of incidence change.

Association between microchimerism and multiple sclerosis in Canadian twins.

Microchimerism, the persistence of foreign cells thought to derive from previous pregnancies, has been associated with autoimmune diseases. A maternal parent-of-origin effect in MS remains unexplained. We tested for microchimerism in monozygotic and dizygotic twin-pairs with MS.