Estimating the Genetic Risk of First-Degree Relatives for Chronic Diseases Using the Short Tandem Repeat Score as Model of Polygenic Inheritance

Abstract

This study aims to establish a genetic risk assessment model based on a score of short tandem repeats (STRs) of polygenic inheritance. A total of 396 children and their biological parents were collected for STR genotyping. The numbers of tandem repeats of two alleles in one STR locus were assumed to be a quantitative genetic strength for disease incidence. The sums of 19 STR loci were considered a quantitative genetic strength per individual. Various thresholds of the STRs between paternal, maternal, and childhood data were recorded. As an exemplar, for thresholds of 25%, the first quarter = 1. All other samples = 0. The consistency rate for heredity (CH) was calculated from the difference in the morbidity of children between parents with and without disease groups. The ratio of observed CH to expected CH was defined as the heredity index (HI). Actual Pedigree data (finger-crossing test) confirmed the accuracy of the STR score. The genetic risk of first-degree relatives could be estimated using easily acquired data (incidence in an unrelated population). Our findings can provide a polygenic genetic model for estimating the incidence and genetic risk of chronic disease in first-degree relatives.