A method for screening for disease in a genomic sample is includes receiving a representation of a reference genome comprising a sequence of symbols. The presence of a predicted mutational event is identified in a location of the reference genome. An alternate path is created in the reference genome representing the predicted mutational event. A plurality of sequence reads are obtained from a genomic sample, wherein at least one sequence read comprises at least a portion of the predicted mutational event. The at least one sequence read is then mapped to the reference genome and a location is determined corresponding to the predicted mutational event. The predicted mutational event is then identified as present in the genomic sample. The method may be used to detect evidence of non-allelic homologous recombination (NAHR) occurring in genomic samples.