Genetic screening currently includes the analysis of coding exons and exon/intron junctions followed by sequencing and deletion/duplication testing of KRIT1, CCM2, and PDCD10. Investigation on new genes responsible for CCM pathology is still ongoing, but it seems to be more likely that the familial cases negative for mutations in the three genes actually carry a pathogenic variant not identified by the commonly used diagnostic methods (e.g., a variant outside the screened exonic regions, deep intron variants, or a copy number neutral genomic rearrangement in one of the three genes) [9]. The gene discussed is CCM2; the disease is cerebral cavernous malformation.