Revealing the Superpowers of PrimPol: rescuing replicating microsatellites

Reid, J. E., & Fischer, T. (2019). The EMBO Journal, e101298. doi:10.15252/embj.2018101298

Error‐free replication of repetitive stretches of DNA is crucial for human health, as more than 30 hereditary developmental and neurological diseases are linked to changes in length of microsatellites, where the repeating unit is < 9 nucleotides. Friedreich's ataxia (FRDA) is one such repeat expansion disease, exhibiting a large number of GAA repeats in the first intron of the FXN gene. Expansion of (GAA)n results in reduced levels of the FXN protein. Normal FXN alleles have < 12 repeats, while disease‐associated alleles often have 600–900 repeats. Therefore, it appears there is a limit to the number of (GAA)n repeats that can be present before this becomes damaging.