One-step NGS molecular analysis of the CFTR gene on newborn dried blood spots gives a higher diagnostic sensitivity in affected and carrier subjects: A pilot study.

BACKGROUND: Cystic fibrosis is the most common hereditary recessive disease with an incidence of about 1:2500/3000. It has long been known that the disease is caused by deleterious mutations in the CFTR gene. Conventionally, the disease is diagnosed in several phases. The analysis of all the possible disease-causing molecular alterations is time consuming and may not lead to a definitive diagnosis in several cases. Consequently, we propose, in this paper, a rapid sequencing method that, in a single procedural asset, reveals the presence of small mutations and also the copy number variants (CNVs) from the DNA extracted from the Guthrie Spot. MATERIALS AND METHODS: We first sequenced 30 blood spots, then we validated the method on 100 spots that underwent both traditional analyses and this complete NGS sequencing, and lastly, we tested the strategy on patients who normally do not reach the molecular sequencing step because of low level of Immune-Reactive Trypsinogen. RESULTS: Using this procedure, we identified 97 variants in the CFTR gene of our samples and 6 CNVs. Notably, the significant data were obtained in the group of patients with borderline or negative IRT who routinely would not undergo molecular testing. We also identified 6 carriers of "disease-causing" variants. CONCLUSION: This method is very robust. Indeed, there was a 100% concordance with Sanger sequencing validation, and 6 mutation carriers were identified who normally escaped molecular testing with actual conventional procedure. There were also 3 duplications of almost the entire gene in heterozygosity, which were not seen with traditional methods. Being quick and easy to perform, we suggest that complete sequencing of the CFTR gene, as in this study be considered for all newborns.

Multi-gene panel testing increases germline predisposing mutations' detection in a cohort of breast/ovarian cancer patients from Southern Italy.

Breast cancer is the most common neoplasia in females worldwide, about 10% being hereditary/familial and due to DNA variants in cancer-predisposing genes, such as the highly penetrant BRCA1/BRCA2 genes. However, their variants explain up to 25% of the suspected hereditary/familial cases. The availability of NGS methodologies has prompted research in this field. With the aim to improve the diagnostic sensitivity of molecular testing, a custom designed panel of 44 genes, including also non-coding regions and 5' and 3' UTR regions, was set up. Here, are reported the results obtained in a cohort of 64 patients, including also few males, from Southern Italy. All patients had a positive personal and/or familial history for breast and other cancers, but tested negative to routine BRCA analysis. After obtaining their written informed consent, a genomic DNA sample/patient was used to obtain an enriched DNA library, then analyzed by NGS. Sequencing data analysis allowed the identification of pathogenic variants in 12 of tested patients (19%). Interestingly, MUTYH was the most frequently altered gene, followed by RNASEL, ATM, MSH6, MRE11A, and PALB2 genes. The reported resultsreinforce the need for enlarged molecular testing beyond BRCA genes, at least in patients with a personal and familial history, strongly suggestive for a hereditary/familial form. This gives also a hint to pursue more specific precision oncology therapy.

Evaluation of a Four-Gene Panel for Hereditary Cancer Risk Assessment.

BRCA1/2 are tumor suppressor genes involved in DNA double-strand break repair. They are the most penetrant genes for hereditary breast and ovarian cancers, but pathogenic variants in these two genes can be identified only in a fraction of hereditary cases. Following the diffusion of BRCA molecular testing and the availability of specific therapeutic strategies for the management of pathogenic variant carriers, the demand for the analysis of additional predisposing genetic factors has increased. Indeed, there is accumulating evidence regarding the role of other genes, including CHEK2 and PALB2. Both of them are involved in the same molecular pathway as BRCA genes, with CHEK2 being responsible for cell cycle stopping to allow the repair of DNA double-strand breaks and PALB2 being able to interact with BRCA1 and activate BRCA2. Thus, their role as additional hereditary cancer predisposing factors is intriguing. Accordingly, guidelines for hereditary cancer risk assessment have been updated to include the criteria for additional genes testing. In this context, we validated a commercially available kit allowing for the simultaneous analysis of BRCA1, BRCA2, CHEK2 and PALB2. Forty-eight patients, already tested for BRCA mutational status, were re-analyzed in the present study. Results comparison showed that the tested method was able to correctly identify all the variants previously detected in the same patients. In particular, all single-nucleotide variants and small indels were correctly identified. Moreover, two copy number variants, included to assess the software's performance in detecting this kind of gene alteration, were also detected. Even if copy number variant estimation still requires confirmation by a molecular technique to avoid false positive results, it is able to reduce the number of patients requiring multiplex ligation probe amplification analysis, positively impacting the test's turnaround time. Finally, since the time and costs of the analysis are similar to those required just for BRCA genes, this strategy may be affordable for providing a more comprehensive test for hereditary cancer risk assessment.

A multi-gene panel beyond BRCA1/BRCA2 to identify new breast cancer-predisposing mutations by a picodroplet PCR followed by a next-generation sequencing strategy: a pilot study.

By analyzing multiple gene panels, next-generation sequencing is more effective than conventional procedures in identifying disease-related mutations that are useful for clinical decision-making. Here, we aimed to test the efficacy of an 84 genes customized-panel in BRCA1 and BRCA2 mutation-negative patients. Twenty-four patients were enrolled in this study. DNA libraries were prepared using a picodroplet PCR-based approach and sequenced with the MiSeq System. Highly putative pathogenic mutations were identified in genes other than the commonly tested BRCA1/2: 2 pathogenic mutations one in TP53 and one in MUTYH; 2 missense variants in MSH6 and ATM, respectively; 2 frameshift variants in KLLN, and ATAD2, respectively; an intronic variant in ANPEP, and 3 not functionally known variants (a frameshift variant in ATM a nonsense variant in ATM and a missense variant in NFE2L2). Our results show that this molecular screening will increase diagnostic sensitivity leading to a better risk assessment in breast cancer patients and their families. This strategy could also reveal genes that have a higher penetrance for breast and ovarian cancers by matching gene mutation with familial and clinical data, thereby increasing information about hereditary breast and ovarian cancer genetics and improving cancer prevention measures or therapeutic approaches.

Fast Detection of a BRCA2 Large Genomic Duplication by Next Generation Sequencing as a Single Procedure: A Case Report.

The aim of this study was to verify the reliability of a next generation sequencing (NGS)-based method as a strategy to detect all possible BRCA mutations, including large genomic rearrangements. Genomic DNA was obtained from a peripheral blood sample provided by a patient from Southern Italy with early onset breast cancer and a family history of diverse cancers. BRCA molecular analysis was performed by NGS, and sequence data were analyzed using two software packages. Comparative genomic hybridization (CGH) array was used as confirmatory method. A novel large duplication, involving exons 4-26, of BRCA2 was directly detected in the patient by NGS workflow including quantitative analysis of copy number variants. The duplication observed was also found by CGH array, thus confirming its extent. Large genomic rearrangements can affect the BRCA1/2 genes, and thus contribute to germline predisposition to familial breast and ovarian cancers. The frequency of these mutations could be underestimated because of technical limitations of several routinely used molecular analysis, while their evaluation should be included also in these molecular testing. The NGS-based strategy described herein is an effective procedure to screen for all kinds of BRCA mutations.

A Novel Pathogenic BRCA1 Splicing Variant Produces Partial Intron Retention in the Mature Messenger RNA.

About 10% of all breast cancers arise from hereditary mutations that increase the risk of breast and ovarian cancers; and about 25% of these are associated with the BRCA1 or BRCA2 genes. The identification of BRCA1/BRCA2 mutations can enable physicians to better tailor the clinical management of patients; and to initiate preventive measures in healthy carriers. The pathophysiological significance of newly identified variants poses challenges for genetic counseling. We characterized a new BRCA1 variant discovered in a breast cancer patient during BRCA1/2 screening by next-generation sequencing. Bioinformatic predictions; indicating that the variant is probably pathogenetic; were verified using retro-transcription of the patient's RNA followed by PCR amplifications performed on the resulting cDNA. The variant causes the loss of a canonic donor splice site at position +2 in BRCA1 intron 21; and consequently the partial retention of 156 bp of intron 21 in the patient's transcript; which demonstrates that this novel BRCA1 mutation plays a pathogenetic role in breast cancer. These findings enabled us to initiate appropriate counseling and to tailor the clinical management of this family. Lastly; these data reinforce the importance of studying the effects of sequence variants at the RNA level to verify their potential role in disease onset.

The molecular analysis of BRCA1 and BRCA2: Next-generation sequencing supersedes conventional approaches.

BACKGROUND: Accurate and sensitive detection of BRCA1/2 germ-line mutations is crucial for the clinical management of women affected by breast cancer, for prevention and, notably, also for the identification of at-risk healthy relatives. The most widely used methods for BRCA1/2 molecular analysis are Sanger sequencing, and denaturing high performance liquid chromatography (dHPLC) followed by the Sanger method. However, recent findings suggest that next-generation sequencing (NGS)-based approaches may be an efficient tool for diagnostic purposes. In this context, we evaluated the effectiveness of NGS for BRCA gene analysis compared with dHPLC/Sanger sequencing. METHODS: Seventy women were screened for BRCA1/2 mutations by both dHPLC/Sanger sequencing and NGS, and the data were analyzed using a bioinformatic pipeline. RESULTS: Sequence data analysis showed that NGS is more sensitive in detecting BRCA1/2 variants than the conventional procedure, namely, dHPLC/Sanger. CONCLUSION: Next-generation sequencing is more sensitive, faster, easier to use and less expensive than the conventional Sanger method. Consequently, it is a reliable procedure for the routine molecular screening of the BRCA1/2 genes.