The Globally search for a Regular Expression and Print matching lines (GREP) strategy: an innovative reanalysis strategy combining bibliographic monitoring with fast GREP directly applied to a massive genomic database to rapidly improve diagnosis

Purpose: Exome sequencing has a diagnostic yield ranging from 25% to 70% in rare diseases and regularly implicates genes in novel disorders. Prospective data reanalysis has demonstrated strong efficacy in improving diagnosis, but poses organizational difficulties for clinical laboratories. We applied a reanalysis strategy based on intensive prospective bibliographic monitoring, and directly applied the Globally search for a Regular Expression and Print matching lines (GREP) command-line to a massive ES database. Methods: For 18 months, we submitted daily the same 5 keywords of interest (( intellectual disability, ( neuro)developmental delay, (neuro)developmental disorder)) to PubMed, to identify recently published, novel disease-gene associations, or new phenotypes in genes already implicated in human pathology. We used the Linux GREP command-line and an in-house script, to collect all variants in these genes from our 5459 exome database. Results: We grepped 128 genes and collected 56 candidate variants in 53 individuals. We confirmed causal diagnosis for 19/128 genes (15%) in 21 individuals, and identified variants of unknown significance for 19/128 genes (15%) in 23 individuals. Altogether, we confirmed pathogenicity in 21/2875 undiagnosed affected probands (0.7%). Conclusion: The GREP command-line is efficient, and less tedious than complete periodical reanalysis. It is an interesting reanalysis strategy to improve diagnosis.