STRs database » LRP12 locus
Overview of repeats
Oculopharyngodistal myopathy (OPDM) is a rare neuromuscular disease and around 200 affected individuals had been reported by 2020, following descriptions beginning in 1977 (Deng et al. (2020)). Type 1 of the disease (OPDM1) is thought to be caused by CGG repeat expansions in the LRP12 gene, as described by Ishiura et al. (2019). LRP12 expansions were identified in a subset of the affected individuals. In 1000 controls, CGG repeats were reported to be 13-45 repeats, except for two of them who showed expanded alleles (Ishiura et al. (2019)).
Kumutpongpanich et al. (2021) identified 65 patients from 59 families with LRP12-associated OPDM; estimated repeat sizes in 60 patients ranged from 85 to 289, with an inverse correlation between repeat length and age at onset. Asymptomatic relatives included an individual with 63 repeats and a father with mosaic alleles of 336 and 364 repeats.
Hobara et al. (2025) subsequently identified expansions of 50-152 repeats in 44 unrelated patients with inherited peripheral neuropathy, predominantly hereditary motor neuropathy or axonal Charcot-Marie-Tooth phenotypes. Most had fewer than 100 repeats, and typical ocular and bulbar OPDM features were uncommon. Controls in that study had 2-28 repeats. Their literature comparison included OPDM expansions as short as 76 repeats, and the authors stated that the pathogenicity of shorter expansions of 50-100 repeats was not yet fully understood.