Polygenic risk scores are being rolled out for embryo screening, but Slate writes that there is a limited understanding of how they work and that they raise ethical concerns.
Slate notes PRSs can rely on between a handful and thousands of SNPs to gauge whether someone is at increased risk of conditions like heart disease or schizophrenia that do not have just one genetic cause and often can be influenced by environmental factors as well. Companies, it adds, are beginning to offer such testing to prospective parents undergoing in vitro fertilization to reduce the risk that their child may develop certain conditions.
However, Slate writes that how most of the SNPs bundled into the score affect disease risk is unknown and that, often, the difference in risk can be small. At the same time, it notes that as most genetic studies have been conducted in people of European ancestry, PRSs are often less useful for individuals of different ancestries.
Slate notes that the "tests aren't necessarily bad or inaccurate. Rather, the science is incomplete — a puzzle with many missing pieces."