ClinVar

Description

This variant deletes 2 nucleotides in exon 20 of the BRIP1 gene, creating a frameshift and premature translation stop signal in the last exon. The mutant transcript is expected to escape nonsense-mediated decay and be expressed as a truncated protein that lacks the last 128 amino acids at the C-terminus. The truncated protein is expected to have a disrupted the TopBP1 binding domain (a.a. 1106-1178) and an acetylation site (p.Lys1249) in the C-terminus, which have been reported to play an important role in DNA replication-stress response and maintaining genomic stability (PMID: 20159562, 21127055, 22792074). To our knowledge, this variant has not been reported in individuals affected with BRIP1-related disorders in the literature. This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Multiple truncation variants that occur downstream of this variant are reported as disease-causing in ClinVar (e.g. c.3390_3393del (p.Tyr1131Leufs*18), ClinVar variation ID: 229712). Although the exact mechanism by which this variant causes disease is yet to be determined, the available evidence indicates that this variant is likely to disrupt normal BRIP1 protein function. Therefore, this variant is classified as Likely Pathogenic.