Unexpected Findings in Hereditary Breast and Ovarian Cancer Syndrome: Low-Level Constitutional Mosaicism in BRCA2.

Hereditary breast and ovarian cancer syndrome (HBOC) is a clinical entity characterized by an increased risk of developing breast and ovarian cancer. The genetic diagnosis is based on the identification of heterozygous germinal variants in HBOC susceptibility genes. However, it has recently been described that constitutional mosaic variants can contribute to the aetiology of HBOC. In constitutional mosaicism, individuals have at least two genotypically distinct populations of cells that arise from an early post-zygote event. The mutational event occurs early enough in development to affect several tissues. It is detected in germinal genetic studies as low variant allele frequency (VAF) variants (<30%) that are generally overlooked during the prioritization process. Constitutional mosaic variants can affect both somatic and germinal cells, and thus can be passed to the offspring and have important consequences for genetic counselling. In this work, we report the c.9648+1G>A mosaic variant in the BRCA2 gene and propose a diagnostic algorithm to deal with potential mosaic findings identified by Next Generation Sequencing (NGS).

A Large Case-Control Study Performed in Spanish Population Suggests That RECQL5 Is the Only RECQ Helicase Involved in Breast Cancer Susceptibility.

Around 50% of the familial breast cancer (BC) cases are estimated to be caused by germline variants in known low-, moderate-, and high-risk susceptibility genes, while the other half is of unknown genetic origin. In the present study, we wanted to evaluate the role of the RECQ helicases, some of which have been studied in the past as candidates, with unclear results about their role in the disease. Using next-generation sequencing (NGS) technology, we analyzed the whole coding sequence of BLM, RECQL1, RECQL4, RECQL5, and WRN in almost 2000 index cases from BC Spanish families that had previously tested negative for the known BC susceptibility genes (BRCAX) and compared the results with the controls extracted from gnomAD. Our results suggest that BLM, RECQL1, RECQL4, and WRN do not play a major role in BC susceptibility. However, in the combined analysis, joining the present results with those previously reported in a series of 1334 BC Spanish patients and controls, we found a statistically significant association between Loss of Function (LoF) variants in RECQL5 and BC risk, with an OR of 2.56 (p = 0.009; 95% CI, 1.18-4.98). Our findings support our previous work and places the RECQL5 gene as a new moderate-risk BC gene.

HCV eradication with DAAs differently affects HIV males and females: A whole miRNA sequencing characterization.

Gender-specific consequences after HCV eradication are unexplored. MicroRNAs (miRNAs) play a crucial role in the immune response against viral infections. However, few have highlighted miRNA role in sex-biased disease or therapy response. We aim to assess gender differences reflected in the miRNA expression of HIV/HCV-coinfected patients who achieve sustained virological response (SVR) with direct acting antivirals (DAAs). We conducted a prospective study of miRNA expression in PBMCs from 28 chronic HIV/HCV-coinfected patients (HIV/HCV) at baseline and after achieving SVR with DAAs. Sixteen HIV-monoinfected patients (HIV) and 36 healthy controls (HC) were used as controls. Identification of significant differentially expressed (SDE) miRNAs was performed with generalized linear model and mixed GLMs. We also explored putative dysregulated biological pathways. At baseline, the HIV/HCV patients showed differences in the miRNA profile concerning the HIV group (165 and 102 SDE miRNAs for males and females, respectively). Gender-stratified analysis of HIV/HCV group at baseline versus at SVR achievement showed higher differences in males (80 SDE miRNAs) than in females (55 SDE miRNAs). After SVR, HIV/HCV group showed similar values to HIV individuals, especially in females (1 SDE miRNA). However, ten miRNAs in males remained dysregulated, which were mainly involved in cancer, fatty acid, and inflammatory pathways. Taken together, our results show gender-biased dysregulation in the miRNA expression profile of PBMCs after HCV eradication with DAAs. These differences were normalized in females, while miRNA profile and their target-related pathways in males lack of normalization, which may be related to a high-risk of developing liver-related complications.

Different HCV Exposure Drives Specific miRNA Profile in PBMCs of HIV Patients.

Micro RNAs (miRNAs) are essential players in HIV and HCV infections, as both viruses modulate cellular miRNAs and interact with the miRNA-mediated host response. We aim to analyze the miRNA profile of HIV patients with different exposure to HCV to explore specific signatures in the miRNA profile of PBMCs for each type of infection. We massively sequenced small RNAs of PBMCs from 117 HIV+ infected patients: 45 HIV+ patients chronically infected with HCV (HIV/HCV+), 36 HIV+ that spontaneously clarified HCV after acute infection (HIV/HCV-) and 36 HIV+ patients without previous HCV infection (HIV). Thirty-two healthy patients were used as healthy controls (HC). Differential expression analysis showed significantly differentially expressed (SDE) miRNAs in HIV/HCV+ (n = 153), HIV/HCV- (n = 169) and HIV (n = 153) patients. We found putative dysregulated pathways, such as infectious-related and PI3K signaling pathways, common in all contrasts. Specifically, putatively targeted genes involved in antifolate resistance (HIV/HV+), cancer-related pathways (HIV/HCV-) and HIF-signaling (HIV) were identified, among others. Our findings revealed that HCV strongly influences the expression profile of PBMCs from HIV patients through the disruption of its miRNome. Thus, different HCV exposure can be identified by specific miRNA signatures in PBMCs.

RAD51D Aberrant Splicing in Breast Cancer: Identification of Splicing Regulatory Elements and Minigene-Based Evaluation of 53 DNA Variants.

RAD51D loss-of-function variants increase lifetime risk of breast and ovarian cancer. Splicing disruption is a frequent pathogenic mechanism associated with variants in susceptibility genes. Herein, we have assessed the splicing and clinical impact of splice-site and exonic splicing enhancer (ESE) variants identified through the study of ~113,000 women of the BRIDGES cohort. A RAD51D minigene with exons 2-9 was constructed in splicing vector pSAD. Eleven BRIDGES splice-site variants (selected by MaxEntScan) were introduced into the minigene by site-directed mutagenesis and tested in MCF-7 cells. The 11 variants disrupted splicing, collectively generating 25 different aberrant transcripts. All variants but one produced negligible levels (<3.4%) of the full-length (FL) transcript. In addition, ESE elements of the alternative exon 3 were mapped by testing four overlapping exonic microdeletions (≥30-bp), revealing an ESE-rich interval (c.202_235del) with critical sequences for exon 3 recognition that might have been affected by germline variants. Next, 26 BRIDGES variants and 16 artificial exon 3 single-nucleotide substitutions were also assayed. Thirty variants impaired splicing with variable amounts (0-65.1%) of the FL transcript, although only c.202G>A demonstrated a complete aberrant splicing pattern without the FL transcript. On the other hand, c.214T>C increased efficiency of exon 3 recognition, so only the FL transcript was detected (100%). In conclusion, 41 RAD51D spliceogenic variants (28 of which were from the BRIDGES cohort) were identified by minigene assays. We show that minigene-based mapping of ESEs is a powerful approach for identifying ESE hotspots and ESE-disrupting variants. Finally, we have classified nine variants as likely pathogenic according to ACMG/AMP-based guidelines, highlighting the complex relationship between splicing alterations and variant interpretation.

TNFAIP3, TNIP1, and MyD88 Polymorphisms Predict Septic-Shock-Related Death in Patients Who Underwent Major Surgery.

BACKGROUND: In many immune-related diseases, inflammatory responses and several clinical outcomes are related to increased NF-κB activity. We aimed to evaluate whether SNPs related to the NF-κB signaling pathway are associated with higher susceptibility to infection, septic shock, and septic-shock-related death in European patients who underwent major surgery. METHODS: We performed a case-control study on 184 patients with septic shock and 212 with systemic inflammatory response syndrome, and a longitudinal substudy on septic shock patients. Thirty-three SNPs within genes belonging to or regulating the NF-κB signaling pathway were genotyped by Agena Bioscience's MassARRAY platform. RESULTS: No significant results were found for susceptibility to infection and septic shock in the multivariate analysis after adjusting for multiple comparisons. Regarding septic-shock-related death, patients with TNFAIP3 rs6920220 AA, TNIP1 rs73272842 AA, TNIP1 rs3792783 GG, and TNIP1 rs7708392 CC genotypes had the highest risk of septic-shock-related death in the first 28 and 90 days. Also, the MyD88 rs7744 GG genotype was associated with a higher risk of death during the first 90 days. Haplotype analysis shows us that patients with the TNIP1 GAG haplotype (composed of rs73272842, rs3792783, and rs7708392) had a lower risk of death in the first 28 days and the TNIP1 AGC haplotype was associated with a higher risk of death in the first 90 days. CONCLUSIONS: The SNPs in the genes TNFAIP3, TNIP1, and MyD88 were linked to the risk of septic-shock-related death in patients who underwent major surgery.