Evaluating the clinical utility of a long-read sequencing-based approach in genetic testing of fragile-X syndrome

•Long-read sequencing-based methods were developed to analyze FMR1 genetic variations.•CAFXS successfully called all the FMR1 CGG expansion.•CAFXS identified 24-bp microdeletions, which was miscalled by conventional methods.•CAFXS allowed for precise constructing FMR1 CGG repeat and AGG interruption pattern.•CAFXS represents a more comprehensive and accurate approach for FXS genetic testing.