Identification and Characterization of an Exonic Duplication in in a Man with Synchronous Breast and Prostate Cancer.

(partner and localizer of ), as indicated by its name, is a -interacting protein that plays an important role in homologous recombination (HR) and DNA double-strand break (DSB) repair. While pathogenic variants of have been well proven to confer an increased risk of breast cancer, data on its involvement in prostate cancer (PrC) have not been clearly demonstrated. We investigated, using targeted next generation sequencing (NGS), a 59-year-old Caucasian man who developed synchronous breast and prostate cancers. This genetic investigation allowed to identify an intragenic germline heterozygous duplication in , implicating intronic repetitive sequences spanning exon 11. This variant was confirmed by multiplex ligation probe amplification (MLPA), and genomic breakpoints have been identified and characterized at the nucleotide level (c.3114-811_3202-1756dup) using an approach based on walking PCR, long range PCR, and Sanger sequencing. RT-PCR using mRNA extracted from lymphocytes and followed by Sanger sequencing revealed a tandem duplication r.3114_3201dup; p.(Gly1068Glufs * 14). This duplication results in the synthesis of a truncated, and most-likely, non-functional protein. These findings expand the phenotypic spectrum of variants and may improve the yield of genetic diagnoses in this field.