No abstract

The IDDM2 locus encoding susceptibility to type 1 diabetes was mapped previously to a 4.1-kb region spanning the insulin gene and a minisatellite or variable number of tandem repeats (VNTR) locus on human chromosome 11p15.5. By 'cross-match' haplotype analysis and linkage disequilibrium mapping, we have mapped the mutation IDDM2 to within the VNTR itself. Other polymorphisms were systematically excluded as primary disease determinants. Transmission of IDDM2 may be influenced by parent-of-origin phenomena. Although we show that the insulin gene is expressed biallelically in the adult pancreas, we present preliminary evidence that the level of transcription in vivo is correlated with allelic variation within the VNTR. Allelic variation at VNTRs may play an important general role in human disease.

We have investigated the correlation between different tumor necrosis factor (TNF) and class II major histocompatibility complex alleles in the lipopolysaccharide- or phytohemagglutinin-induced secretion of TNF-alpha and TNF-beta by human monocytes and peripheral blood mononuclear cells in 87 unrelated Danish male individuals. Significant differences in TNF-alpha secretory capacity between TNF NcoI restriction fragment length polymorphisms, TNFa and TNFc microsatellite alleles and DR alleles were identified. No correlation with TNF-beta secretory capacity was found for any of the markers studied. TNF genotyping allowed us to define four extended HLA haplotypes which correlate with TNF-alpha secretory capacity. Two of these are DR4 positive: DQw8, DR4, TNFB*1, TNFa6, B44, A2 and DQw8, DR4, TNFB*2, TNFa2, B15, A2. Individuals carrying the TNFB*2, TNFa2 haplotype had a higher TNF-alpha secretory capacity than those carrying the TNFB*1, TNFa6 haplotype. In a group of DR3/DR4 heterozygous patients with insulin-dependent diabetes mellitus (IDDM), the frequency of the TNFa2 allele was higher than in HLA-DR matched controls, whereas the TNFa6 allele was more frequent in control individuals. In the DR3/DR4 heterozygous diabetic group 12/26 had the alleles combination DQw8, DR4 (Dw4), C4A3, TNFB*2, TNFa2, B15, whereas only 1/18 controls had this haplotype. This diabetogenic haplotype is identical to the DR4 haplotype which correlates with a higher TNF-alpha response. These observations suggest a direct role for the TNF locus in the pathogenesis of IDDM.

To investigate which aspects of contemporary human Y-chromosome variation in Europe are characteristic of primary colonization, late-glacial expansions from refuge areas, Neolithic dispersals, or more recent events of gene flow, we have analyzed, in detail, haplogroup I (Hg I), the only major clade of the Y phylogeny that is widespread over Europe but virtually absent elsewhere. The analysis of 1,104 Hg I Y chromosomes, which were identified in the survey of 7,574 males from 60 population samples, revealed several subclades with distinct geographic distributions. Subclade I1a accounts for most of Hg I in Scandinavia, with a rapidly decreasing frequency toward both the East European Plain and the Atlantic fringe, but microsatellite diversity reveals that France could be the source region of the early spread of both I1a and the less common I1c. Also, I1b*, which extends from the eastern Adriatic to eastern Europe and declines noticeably toward the southern Balkans and abruptly toward the periphery of northern Italy, probably diffused after the Last Glacial Maximum from a homeland in eastern Europe or the Balkans. In contrast, I1b2 most likely arose in southern France/Iberia. Similarly to the other subclades, it underwent a postglacial expansion and marked the human colonization of Sardinia approximately 9,000 years ago.

Numerous studies of genetic epidemiology and post-genomics in respiratory diseases rely on the use of biobanks, defined as organised biological sample collections with associated personal and clinical data. The use of biobanks is increasing and raises several ethical issues. What are the ethical trends and legal frameworks in the post-genomic era? Are there new issues in relation to the developments of techniques and new study designs? How does this affect the clinician's attitudes and relationship with the patients?The main ethical issues encountered are: informed consent; confidentiality; secondary use of samples and data over time; return of results; and data sharing. Different levels and modalities of dealing with such issues are identified and vary from legally binding measures to ''soft'' regulations, such as ethical recommendations by various committees or professional organisations.A further level of complexity appears with the increasing international dimension of such activities in a context in which national positions vary on those topics. There is a tension between a necessary level of diversity in ethical positions and an indispensable common pedestal of principles and procedures to manage these issues in order to foster research.Current legal and ethical trends favour the facilitation of secondary use of samples, more biobank openness, balanced with a growing attention to dialogue and public/stakeholder consultation, an increased role for research ethics committees and more sophisticated data protection and governance structures.

Loci in the major histocompatibility complex (MHC) on chromosome 6 and the insulin (INS) region on chromosome 11 have been implicated in susceptibility to insulin-dependent diabetes mellitus (IDDM) through candidate gene investigations, but they may account for less than 50% of genetic risk for the disease. Genome-wide linkage studies have led to localization of more than 10 susceptibility loci for insulin-dependent diabetes in the non-obese diabetic (NOD) mouse and the BB rat. Similar studies are now possible in humans through the development of dense genetic maps of highly informative microsatellite loci obtained using polymerase chain reaction analysis. We have applied microsatellite markers from recent Généthon maps, and other highly informative markers, in a genome-wide linkage study in IDDM. Here we report evidence for the localization of a previously undetected susceptibility locus for IDDM in the region of the FGF3 gene on chromosome 11q. Our results shows the potential of genome-wide linkage studies to detect susceptibility loci in IDDM and other multifactorial disorders.

Despite scientific and clinical advances in the field of pharmacogenomics (PGx), application into routine care remains limited. Opportunely, several implementation studies and programs have been initiated over recent years. This article presents an overview of these studies and identifies current research gaps. Importantly, one such gap is the undetermined collective clinical utility of implementing a panel of PGx-markers into routine care, because the evidence base is currently limited to specific, individual drug-gene pairs. The Ubiquitous Pharmacogenomics (U-PGx) Consortium, which has been funded by the European Commission's Horizon-2020 program, aims to address this unmet need. In a prospective, block-randomized, controlled clinical study (PREemptive Pharmacogenomic testing for prevention of Adverse drug REactions [PREPARE]), pre-emptive genotyping of a panel of clinically relevant PGx-markers, for which guidelines are available, will be implemented across healthcare institutions in seven European countries. The impact on patient outcomes and cost-effectiveness will be investigated. The program is unique in its multicenter, multigene, multidrug, multi-ethnic, and multihealthcare system approach.

Asthma, rhinitis, and eczema are complex diseases with multiple genetic and environmental factors interlinked through IgE-associated and non-IgE-associated mechanisms. Mechanisms of the Development of ALLergy (MeDALL; EU FP7-CP-IP; project no: 261357; 2010-2015) studied the complex links of allergic diseases at the clinical and mechanistic levels by linking epidemiologic, clinical, and mechanistic research, including in vivo and in vitro models. MeDALL integrated 14 European birth cohorts, including 44,010 participants and 160 cohort follow-ups between pregnancy and age 20 years. Thirteen thousand children were prospectively followed after puberty by using a newly standardized MeDALL Core Questionnaire. A microarray developed for allergen molecules with increased IgE sensitivity was obtained for 3,292 children. Estimates of air pollution exposure from previous studies were available for 10,000 children. Omics data included those from historical genome-wide association studies (23,000 children) and DNA methylation (2,173), targeted multiplex biomarker (1,427), and transcriptomic (723) studies. Using classical epidemiology and machine-learning methods in 16,147 children aged 4 years and 11,080 children aged 8 years, MeDALL showed the multimorbidity of eczema, rhinitis, and asthma and estimated that only 38% of multimorbidity was attributable to IgE sensitization. MeDALL has proposed a new vision of multimorbidity independent of IgE sensitization, and has shown that monosensitization and polysensitization represent 2 distinct phenotypes. The translational component of MeDALL is shown by the identification of a novel allergic phenotype characterized by polysensitization and multimorbidity, which is associated with the frequency, persistence, and severity of allergic symptoms. The results of MeDALL will help integrate personalized, predictive, preventative, and participatory approaches in allergic diseases.