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Browsing by Subject "FinnGen"

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  • Rögnvaldsson, Sölvi (2023)
    Seasonal variation has affected human societies throughout history, shaping various aspects of life including agriculture, migration patterns and culture. This influence is observed, among others, in the occurrences of diseases such as viral and bacterial infections, cardiovascular disease and mental disorders. While there are a multitude of factors influencing the timing of disease diagnoses, environmental and behavioral, the genetic role has not been explored to the best of our knowledge. The aim of this thesis was to relate genetic variation to seasonal disease risk. To achieve this, the seasonality of 1,759 disease endpoints was assessed in the Finnish population. A subset of 14 diseases were selected and used as input into a statistical modeling framework that was developed to search for genetic variants associated with seasonal disease risk in the FinnGen study population. A total of 9 genome-wide significant loci affecting seasonality were identified, including a top-sQTL, rs41273830[T], in ITGB8 for major depression and a stop-gain variant, rs601338[A], in FUT2 for intestinal infections, the latter also being protective against disease risk. This introduces a new aspect to genetic research, which can both contribute to better understanding how known disease variants affect disease but also finding new disease variants whose effects are currently obscured by seasonal variation.
  • Detrois, Kira Elaine (2023)
    Background/Objectives: Various studies have shown the advantage when incorporating polygenic risk scores (PRSs) in models with classic risk factors. However, systematic comparisons of PRSs with non-genetic factors are lacking. In particular, many studies on PRSs do not even report the predictive performance of the confounders, such as age and sex, included in the model, which are already very predictive for most diseases. We looked at the ability of PRSs to predict the onset of 18 diseases in FinnGen R8 (N=342,499) and compared PRSs with the known non-genetic risk factors, age, sex, Education, and Charlson Comorbidity Index (CCI). Methods: We set up individual studies for the 18 diseases. A single study consisted of an exposure (1999-2009), a washout (2009-2011), and an observation period (2011-2019). Eligible individuals could not have the selected disease of interest inside the disease-free period, which ranged from birth until the beginning of the observation period. We then defined the case and control status based on the diagnoses in the observation period and calculated the phenotypic scores during the exposure period. The PRSs were calculated using MegaPRS and the latest publicly available genome-wide association study summary statistics. We then fitted separate Cox proportional hazards models for each disease to predict disease onset during the observation period. Results: In FinnGen, the model’s predictive ability (c-index) with all predictors ranged from 0.565 (95%CI: 0.552-0.576) for Acute Appendicitis to 0.838 (95% CI: 0.834-0.841) for Atrial Fibrillation. The PRSs outperformed the phenotypic predictors, CCI, and Education, for 6/18 diseases and still significantly enhance onset prediction for 13/18 diseases when added to a model with only non-genetic predictors. Conclusion: Overall, we showed that for many diseases PRSs add predictive power over commonly used predictors - such as age, sex, CCI, and Education. However, many important challenges must be addressed before implementing PRSs in clinical practice. Notably, we will need disease-specific cost- benefit analyses and studies to assess the direct impact of including PRSs in clinical use. Nonetheless, as more research is being conducted, PRSs could play an increasingly valuable role in identifying individuals at higher risk for certain diseases and enabling targeted interventions to improve health outcomes.