Mapping Genes for Type 2 (Non-Insulin Dependent) Diabetes Mellitus
Condition: Genetic Variation; Diabetes
MeSH terms: Diabetes Mellitus
Study type: Observational

Summary: 
      The aim of the project is to positionally clone susceptibility genes for NIDDM. Patients will
      be ascertained in Finland from previous health surveys and hospital discharge records.
      Approximately 400 affected sib pairs will be collected. Families will be chosen who have, at
      most, one parent with NIDDM no history of IDDM. A clinical examination will be undertaken on
      family members and blood drawn for DNA isolation. Covariates such as body weight, blood
      pressure, lipid levels and urinary albumin will also be measured. The unaffected spouse and
      children of a subset of probands will be invited to undergo a frequently-sampled intravenous
      glucose tolerance test (FSIGT) to measure parameters of pancreatic function and peripheral
      insulin resistance (IR). A number of unrelated elderly non-diabetic subjects will also be
      identified to conduct a population-based association analysis.

      The FSIGT analysis will be performed in Los Angeles. The DNA will be shipped to Bethesda
      where a total genomic scan will be performed using semi-automated fluorescence-based
      genotyping technology. Data from Bethesda, Los Angeles and Finland will be sent to Ann Arbor
      where parametric and non-parametric methods will be used to analyse both discrete traits such
      as NIDDM and intermediate traits like IR....
    

Detailed description: 
      The Finland-United States investigation of NIDDM (FUSION) study is a long-term effort to

      identify susceptibility genes for Type 2 diabetes (T2D) and associated quantitative traits.
      This

      involves the phenotyping and DNA analysis of thousands of individuals living in Finland,
      utilizing a study design that was originally based on affected sib pairs. The majority of
      these samples have already been subjected to a genome scan using microsatellite markers and
      the original FUSION samples. Additionally, thousands of other northern European cases and
      controls have been subjected to genome-wide association (GWA) analysis and/or fine mapping as
      part of the FUSION study. More recently, the opportunity provided by the lowered sequencing
      costs have allowed targeted and/or whole genome sequencing of many of these individuals.
    

Observational model: Case-Control
Time perspective: Other
Sampling method: Non-Probability Sample
Study population: 
        A large majority of the sample population resides in various parts of Finland and are of
        Finnish descent. The Finnish population provides an ideal basis for studies of complex
        genetic diseases such as T2D due to its relative genetic and environmental homogeneity,
        excellent data sources, and a population strongly supportive of biomedical research.
        Individuals with or without diabetes (type2 or monogenic forms of diabetes) have been
        collected.
      
Biospecimen description: 
      Blood DNA, Adipose, Muscle, Fibroblast, Serum
    
Keywords: Monogenic Diabetes; Type 2 Diabetes Mellitus; QTL