A synonymous germline variant PALB2 c.18G>T (p.Gly6=) disrupts normal splicing in a family with pancreatic and breast cancers.

PURPOSE: Mutations in PALB2 have been associated with a predisposition to breast and pancreatic cancers. This study aims to characterize a novel PALB2 synonymous variant c.18G>T (p.Gly6=) identified in a family with pancreatic and breast cancers. METHODS: The PALB2 c.18G>T (p.Gly6=) variant in this family was identified using Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets (MSK-IMPACT™). RT-PCR and subsequent cloning were performed to investigate whether this variant affects normal splicing. RESULTS: This variant completely disrupts normal splicing and leads to several abnormal transcripts, which presumably leads to premature protein truncation. The major abnormal transcript resulted in a deletion of 32 base pairs in exon 1 and frameshift. CONCLUSIONS: Our results indicate that the PALB2 c.18G>T (p.Gly6=) variant is likely pathogenic. This study provided important laboratory evidence for classification of this variant and guided improved patient management.