Myotonic dystrophy gene changes found in 1 in 1,527 people
Across 985,026 participants, disease-causing DNA expansions occurred in about 1 in 1,527, compared with earlier disease prevalence estimates of 1 in 3,000–8,000.
Researchers analysed genome data from 985,026 participants in Genomics England, UK Biobank and the All of Us Research Program in an observational study. They looked for unusually long stretches of repeated DNA that cause myotonic dystrophy type 1, a disorder affecting several body systems.
They identified disease-causing expansions in 645 participants, or 0.07%. Most had no previous diagnosis of the disorder. Expansions appeared across all ancestry groups. In UK Biobank, expansions were associated with higher odds of a heart diagnosis. The strongest links involved problems with the heart’s electrical signalling and irregular heartbeats. In Genomics England and UK Biobank, about one in ten people with an expansion had a cataract diagnosis before age 55. Cataracts cloud the eye’s lens.
Why it matters
The focus on cataracts before age 55 addressed whether the timing of eye disease could help identify an inherited disorder. The authors supported genetic testing in specified heart and eye diagnostic pathways to enable earlier detection.
Caveats
These observational data estimated the prevalence of disease-causing DNA expansions, not clinically diagnosed disease. The study did not test whether genetic screening improved health outcomes.
