Overview of repeats
Oculopharyngodistal myopathy (OPDM) is a rare neuromuscular disease and around 200 affected individuals have been found to date since 1977 (Deng et al., 2020). Type 1 of the disease (OPDM1) is thought to be caused by CGG repeat expansions in the LRP12 gene which was recently described by Ishiura et al. (2019). They discovered repeats in the length of 280 or 380 bp (corresponding to ~93 or ~127 repeats, respectively) in the affected individuals. However, this was only observed in a subset of the samples. In 1000 controls, CGG repeats were reported to be between 13-45 repeats, except for two of them who showed expanded alleles (Ishiura et al., 2019).