Principal Component and Linkage Analysis of Cardiovascular Risk Traits in the Norfolk Isolate

Abstract

Objective(s): An individual’s risk of developing cardiovascular disease (CVD) is influenced by genetic factors. This study focussed on mapping genetic loci for CVD-risk traits in a unique population isolate derived from Norfolk Island. Methods: This investigation focussed on 377 individuals descended from the population founders. Principal component analysis was used to extract orthogonal components from 11 cardiovascular risk traits. Multipoint variance component methods were used to assess genome-wide linkage using SOLAR to the derived factors. A total of 285 of the 377 related individuals were informative for linkage analysis. Results: A total of 4 principal components accounting for 83% of the total variance were derived. Principal component 1 was loaded with body size indicators; principal component 2 with body size, cholesterol and triglyceride levels; principal component 3 with the blood pressures; and principal component 4 with LDL-cholesterol and total cholesterol levels. Suggestive evidence of linkage for principal component 2 (h² = 0.35) was observed on chromosome 5q35 (LOD = 1.85; p = 0.0008). While peak regions on chromosome 10p11.2 (LOD = 1.27; p = 0.005) and 12q13 (LOD = 1.63; p = 0.003) were observed to segregate with principal components 1 (h² = 0.33) and 4 (h² = 0.42), respectively. Conclusion(s): This study investigated a number of CVD risk traits in a unique isolated population. Findings support the clustering of CVD risk traits and provide interesting evidence of a region on chromosome 5q35 segregating with weight, waist circumference, HDL-c and total triglyceride levels.

Prevalence and predictors of refractive error in a genetically isolated population: the Norfolk Island Eye Study

“…Notably, there was no difference in the mean MSE between Pitcairn and non‐Pitcairn populations 18 . To date, the Norfolk Island population has been a very useful population in which to study the genetic epidemiology of cardiovascular traits, 40,41 and it is hoped will yield significant discoveries in ophthalmic genetics and epidemiology. Indeed there is considerable evidence suggesting an inheritable contribution to the aetiology of refractive error, 42 as well as in the biometric components that are associated closely with the presence and development of refractive error 43 .…”

“…Of the people with two eyes available (n = 538), all-age prevalence of anisometropia (inter-eye difference Ն 1.0 D) was 14.8%. Prevalence in people aged 15-29 was 5.5%, in people aged 30-39 was 10.0%, 5.7% in people aged [40][41][42][43][44][45][46][47][48][49]11.6% in people aged 50-59, 16.4% in people 60-69, and rising to 34.8% in people aged 70 and over. Prevalence in women was 11.9%, and in men 14.8%.…”

Principal component analysis of cardiovascular risk traits in three generations cohort among Indian Punjabi population

“…Presently, principal component factor analysis (PCFA) has been used to extract independent factors from large amount of inter-correlated factors [1,11,12] . The PCFA is a statistical method of data reduction which has been used in past many years to identify the clustering of risk factors of the metabolic syndrome [1,2,11,13] . All these studies have consistently found multiple factors.…”

Phenotypic characterization of class II malocclusion using two dimensional photographic measurements

“…PCA was used to derive quantitative phenotypes and CA to identify phenotypically homogenous groups of individuals. PCA and CA have been used effectively to develop well defined phenotypes for genetic mapping of complex traits such as cardiovascular disease (Cox, Bellis et al 2009) and schizophrenia (Lin, Liu et al 2009).…”