Polygenic risk score prediction of complex diseases in companion animals: prospects, opportunities, and challenges

Polygenic risk scores (PRSs) have become a crucial tool in biomedical research, offering insights into the genetic predispositions underlying complex diseases. Initially developed in human health, PRS values are analogous to estimated breeding values used in livestock for selecting desirable traits. While PRS risk prediction has gained traction in human health due to many genome-wide association studies and well-established phenotypic databases, companion animal research suffers from smaller sample sizes, limited genomic resources, and highly diverse genetic architectures across breeds. Genetic heterogeneity among companion animals, particularly dogs, complicates PRS risk prediction, as breed-specific variants and genetic architectures often require tailored prediction models. However, the use of PRS risk prediction in companion animals remains relatively underexplored. This paper investigates the reasons for this limited research and addresses the unique challenges and future opportunities that hinder the broader adoption of PRS risk prediction in companion animals, compared to humans and production animals.