[Exact localization of several fragile sites remains uncertain. The example of fra(10) sensitive to folate].

The localization of the folate-sensitive fragile site first proposed to be at 10q24.2 was further assigned to 10q23. The study of one case using several banding techniques, and of 12 other unpublished cases studied with R-banding confirm the original localization, at the junction between 10q24.1 and 10q24.2. Because many reports propose that fragile sites induce further anomalies, we suggest that a re-study of the exact location of these sites with accurate methods is in order if misinterpretations are to be avoided.