Microdeletions in patients with X-linked muscular dystrophy: molecular-clinical correlations.

The DNA from 68 patients with X-linked (Duchenne and Becker) muscular dystrophy belonging to 49 unrelated families was analyzed for microdeletions using 13 closely linked or gene-specific DNA-markers. Fourteen patients from eight families showed a deletion involving a least one of the markers used, giving a deletion frequency of 16%. The proportion of families with deletions was 36% in the Becker and 8% in the Duchenne form of the disease. With one exception, the extent of the deletion was different in different families. All living, affected males from the same family carried the same deletion. The extent or the localization of the deletion did not correlate with clinical features such as severity of disease or mental retardation.