Genotype error due to low-coverage sequencing induces uncertainty in polygenic scoring

Am J Hum Genet. 2023 Aug 3;110(8):1319-1329. doi: 10.1016/j.ajhg.2023.06.015. Epub 2023 Jul 24.

Abstract

Polygenic scores (PGSs) have emerged as a standard approach to predict phenotypes from genotype data in a wide array of applications from socio-genomics to personalized medicine. Traditional PGSs assume genotype data to be error-free, ignoring possible errors and uncertainties introduced from genotyping, sequencing, and/or imputation. In this work, we investigate the effects of genotyping error due to low coverage sequencing on PGS estimation. We leverage SNP array and low-coverage whole-genome sequencing data (lcWGS, median coverage 0.04×) of 802 individuals from the Dana-Farber PROFILE cohort to show that PGS error correlates with sequencing depth (p = 1.2 × 10-7). We develop a probabilistic approach that incorporates genotype error in PGS estimation to produce well-calibrated PGS credible intervals and show that the probabilistic approach increases classification accuracy by up to 6% as compared to traditional PGSs that ignore genotyping error. Finally, we use simulations to explore the combined effect of genotyping and effect size errors and their implication on PGS-based risk-stratification. Our results illustrate the importance of considering genotyping error as a source of PGS error especially for cohorts with varying genotyping technologies and/or low-coverage sequencing.

Keywords: PGS; PGS error; effect sizes; genotype error; lcWGS; risk stratification; uncertainty.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Genomics* / methods
  • Genotype
  • Polymorphism, Single Nucleotide* / genetics
  • Uncertainty
  • Whole Genome Sequencing