Dystrophinopathy patient data as a guide to interpretation of pregestational female population screening for DMD gene variants.

Pregestational population screening of healthy females for copy number variants in DMD gene has raised numerous challenges regarding the interpretation and disclosure of these findings. Our objective was to analyze data from a local dystrophinopathy patient database, in comparison to population screening results. Utilizing the "Little steps" association registry for children with dystrophinopathy, we classified genetic findings (out-of-frame, in-frame, or difficult-to-predict) in 231 DMD and 90 BMD male patients. A comparison was made with a previously published cohort of 162 female carriers identified through population screening. Duplications classified as "difficult to predict" were absent in DMD/BMD patients, as opposed to 45.1% of women analyzed in the scope of population screening (p < 0.0001). While the distribution of deletions did not differ between the groups, significantly higher proportion of duplications initiated at the proximal hot spot in the DMD/BMD cohort (87.1%), vs. only 11.7% in women analyzed through population screening (p = 0.0038). Notably, duplications initiating in the dp427c promoter area were noted only in the latter cohort (n = 62). Local databases of dystrophinopathy patients can facilitate analysis and reporting of pregestational female population screening results. These conclusions facilitate future introductions of population screening genetic tests for diseases with variable presentation.