201. Bivariate mixture models for the joint distribution of repeated serum ferritin and transferrin saturation measured 12 years apart in a cohort of healthy middle-aged Australians
- Author
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Katrina J. Allen, John L. Hopper, Dallas R. English, Wen-Pin Chen, Christine E. McLaren, Martin B. Delatycki, Lyle C. Gurrin, Graham G. Giles, and Nadine A. Bertalli
- Subjects
Male ,Heredity ,Physiology ,Cardiovascular Medicine ,01 natural sciences ,Biochemistry ,010104 statistics & probability ,Medicine and Health Sciences ,chemistry.chemical_classification ,0303 health sciences ,education.field_of_study ,Multidisciplinary ,Liver Diseases ,Homozygote ,Statistics ,Transferrin ,Middle Aged ,Genetic Mapping ,Cardiovascular Diseases ,Ellipses ,Hereditary hemochromatosis ,Cohort ,Physical Sciences ,Medicine ,Engineering and Technology ,Female ,Hemochromatosis ,HFE Protein ,Genetic Engineering ,Research Article ,Biotechnology ,Adult ,General Science & Technology ,Science ,Population ,Mutation, Missense ,Geometry ,Variant Genotypes ,Bioengineering ,Bivariate analysis ,Gastroenterology and Hepatology ,Biology ,Genetic Predisposition ,Models, Biological ,03 medical and health sciences ,MD Multidisciplinary ,medicine ,Genetics ,Cardiovascular Diseases in Women ,Humans ,0101 mathematics ,education ,Hemochromatosis Protein ,030304 developmental biology ,Ferritin ,Transferrin saturation ,Contingency Tables ,Australia ,Biology and Life Sciences ,Proteins ,Protein Complexes ,medicine.disease ,chemistry ,Amino Acid Substitution ,Ferritins ,Genetics of Disease ,Women's Health ,Mathematics - Abstract
Homozygosity for the p.C282Y substitution in the HFE protein encoded by the hemochromatosis gene on chromosome 6p (HFE) is a common genetic trait that increases susceptibility to iron overload. McLaren et al. used bivariate mixture modeling to analyze the joint population distribution of transferrin saturation (TS) and serum ferritin concentration (SF) measured for participants in the Hemochromatosis and Iron Overload Screening (HEIRS) Study. They identified four components (C1, C2, C3, and C4) with successively increasing means for TS and SF. They demonstrated that bivariate mixture modeling in TS and SF reflect the genetic locus of HFE and may isolate p.C282Y homozygotes from the general population. In the current study we used data from the another large cohort, the Australian HealthIron study of genetic and environmental modifiers of hereditary hemochromatosis, to validate the component analysis approach, to examine stability of component proportions over time and to determine if TS and SF values from an individual move between components at baseline and follow-up. Because sampling fractions from each p.C282Y / p.H63D genotype stratum are not equal, we used frequency weights based on the inverse of the probability of selection for invitation to participate. In the weighted female analytic cohorts, C4 captured most of C282Y homozygotes, and C2 was the largest component. We identified four components from the weighted male analytic cohort and C4 captured most of p.C282Y homozygotes. The bivariate mixture modeling approach suggested that the model is transferable from one white population to another, although estimated means within components may differ.
- Published
- 2018
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