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Background Due to the limited availability of mRNA analysis data, the number of exonic variants resulting in splicing impairment is underestimated although aberrant splicing correction is a promising therapeutic option to treat monogenic diseases, including choroideremia (CHM), a rare X‐linked eye disorder arising from sequence alteration of the CHM gene. Herein we report an exonic frameshift variant associated with an mRNA splicing alteration that leads to a CHM hypomorphic allele. Methods Total RNA and genomic DNA were extracted from peripheral blood of a patient affected by a mild form of CHM. The CHM gene was analyzed by PCR‐based methods and Sanger sequencing. Results Besides the known c.1335dup frameshift variant, mRNA analysis revealed a splicing alteration that restored the reading frame of the mutant transcript, likely leading to an aberrant protein with residual activity. Bioinformatic analyses identified novel putative exonic splicing enhancer elements and provided clues that also pre‐mRNA secondary structure should be taken into account when exploring splicing mechanisms. Conclusion A careful molecular characterization of the c.1335dup variant's effect explains the relationship between genotype and phenotype severity in a CHM patient and provides new perspectives for the study of therapeutic strategies based on splicing correction in human diseases., The number of exonic variants resulting in splicing impairment is underestimated because they are primary considered “changing‐code” mutations. We reveal a pathogenic CHM frameshift variant associated with an exon skipping that restores the gene reading frame. The mRNA alteration transforms a potential null allele into a hypomorphic disease‐allele that mitigates the phenotype severity.

Background During the twentieth century, frontotemporal dementia (FTD) was often misdiagnosed, confused with Alzheimer's disease or psychiatric disorders, jeopardizing care and research. Objective To analyze the FTD genes in the DNA samples of patients belonging to families clinically classified as probable Alzheimer's disease (FAD) in the early 1990s and not carrying mutation in the three main genes linked to FAD (Presenilin 1, Presenilin 2, and Amyloid precursor protein). Methods The genetic screening was performed on 63 probands diagnosed as FAD before the early 2000s. Results Four patients out of the 63 studied (4/63, 6.3%) resulted as carrying four different GRN genetic variations: p.T272SfsX10, p.R110X, p.C149LfsX10, and p.W304C. The first two mutations (p.T272SfsX10, p.R110X) are the most frequent ones in Italy in FTD patients; the latter two (p.C149LfsX10 and p.W304C) are not described in the scientific literature. Conclusion Our data suggest that it can be important to re-examine FAD patients diagnosed when the FTD spectrum was not well recognized and the causative FTD genes had not yet been identified. Moreover, we propose initially analyzing genes associated with the first form of suspected dementia and, if the results are negative, studying genes implicated in the other form of dementia.

Pathogenic germline variants in the BAP1 tumor suppressor gene can cause a cancer syndrome called BAP1 tumor predisposition syndrome (BAP1-TPDS), which is characterized by predisposition to mesothelioma, melanoma, renal cell carcinoma, basal cell carcinoma, and other tumors. Other genes that may predispose to mesothelioma are CDKN2A and DNA repair genes. Asbestos exposure has often been reported in patients with malignant pleural mesothelioma (MPM) and germline variants in BAP1, but this exposure has never been quantified. We aimed to search for germline variants in BAP1 among 25 new Italian probands with suspected BAP1-TPDS, summarize the prevalence of these variants in 39 Italian patients with familial MPM and other tumors recruited over a 5-year period, and compare cumulative asbestos exposure in 14 patients with MPM and pathogenic germline variants in BAP1, CDKN2A, or DNA repair genes with that of 67 patients without germline variants in 94 cancer-predisposing genes. We report here a new pathogenic germline variant in BAP1: c.783 + 2 T > C. The prevalence of pathogenic germline variants in BAP1 was 7.7% among patients with familial MPM (3/39). Patients with pathogenic germline variants in BAP1, CDKN2A, or DNA repair genes showed lower cumulative asbestos exposure than patients without germline variants in 94 cancer-predisposing genes (P = .00002). This suggests an interaction between genetic risk factors and asbestos in the development of mesothelioma.

The detection of somatic mutations in a tumor represents a valuable tool for tumor characterization and provides the clinicians with information for setting up the most appropriate therapy. KRAS mutations in codons 12 and 13 are important biomarkers routinely analyzed in the clinic for the management of anti-EGFR treatment in colorectal carcinoma (CRC). Here we report a sensitive and inexpensive assay for KRAS mutations based on a PNA-mediated PCR clamping. The assay displays very high sensitivity (0.7%) and specificity (96.7%) when compared to traditional sequencing (SS) and pyrosequencing (PS), two of the most commonly and routinely used methods employed today by diagnostic laboratories. Furthermore, the PNA assay requires only basic and low-cost laboratory equipment, in contrast with all the most recent PCR-based technologies, which are highly sensitive but also much more expensive. Finally, despite the PNA assay does not allow for the definition of specific mutations, it is the cheapest and easiest screening method to firstly stratify wild-type and mutated patients, information that is strictly necessary to clinicians for the management of CRC and anti-EGFR treatment.

Summary Birt-Hogg-Dube syndrome (BHD) is an autosomal dominant condition characterised clinically by skin fibrofolliculomas, pulmonary cysts, spontaneous pneumothorax, and renal cancer. The condition is caused by germline mutations in the FLCN gene, which encodes folliculin; the function of this protein is largely unknown, although FLCN has been linked to the mTOR pathway. The availability of DNA-based diagnosis has allowed insight into the great variation in expression of FLCN , both within and between families. Patients can present with skin signs and also with pneumothorax or renal cancer. Preventive measures are aimed mainly at early diagnosis and treatment of renal cancer. This Review gives an overview of current diagnosis and management of BHD.

It is commonly believed that tumor cells treated with anticancer agents, chemotherapy and/or radiation, die by apoptosis and that tumors which do not undergo apoptosis are resistant to treatment. In this study, we investigated the molecular basis underlying cisplatin cytotoxicity in the murine teratocarcinoma F9 cell line to see whether irradiation enhances cisplatin-induced cytotoxicity. We compared the apoptosis induced by chemo and/or radiotherapy with other cellular effects such as cell survival, clonogenic capability, cell cycle perturbation, expression of p53 and p53-related mRNAs, and necrosis. When combined with radiation, a clear additive cytotoxic effect of cisplatin was demonstrated. We found that both cisplatin and radiation induced cell death, but the level of induced apoptosis was low and there was no correlation with the results of the clonogenic assays: we noted a difference between cytotoxic effects in the clonogenic assay and the extent of apoptosis by fluorescence-activated cell sorter analysis, suggesting that cell killing reflected not only apoptosis but also cell cycle arrest, and that apoptosis, cell kinetics and clonogenicity suppression were independent processes.

Introduction K-Ras mutations, occurring prevalently within codons 12/13, are detected in different cancer types including colorectal carcinoma (CRC) and might be responsible for resistance to anti-EGFR monoclonal antibodies (Cetuximab®) treatment. A sensitive method for K-Ras mutations detection is therefore crucial issue for choosing the most appropriate therapy. Currently, Sanger sequencing (SS) is accepted as gold standard method for mutational analysis but it is time-consuming and cost-ineffective. In addition, since in tumor analysis mutated clone may be present at different percentage, the SS sensitivity limit of 15-20% is crucial. Pyrosequencing (PS) has 5% detection limit, but still cost-ineffective, not largely available and shown a grey area (5-10%) in which genotype remains undeterminable. Therefore, a more sensitive method for detecting k-Ras mutations represents still a challenge. In this study we developed a novel, sensitive, friendly to use and very cheap assay for K-Ras mutations in CRC, based on PNA-directed PCR-clamping. Methods PNAs are synthetic molecules acting as potent DNA mimic in terms of sequence specific hybridization. As consequence, PNA/DNA heteroduplex is thermodynamically more stable than DNA/DNA counterpart but PNA cannot be extended by polymerase to function as a primer. Based on this, we designed a PNA molecule and one of the PCR primers perfectly matching the WT K-Ras sequence (encompassing codons 12/13), thus leading to a direct competition towards complementary template genomic DNA. In WT samples, perfect matching occurs because PNA-template hybridization is favoured and DNA amplification suppressed. By contrast, in case of mutated K-ras a single base pair mismatch will strongly impair the PNA-template stability favouring PCR amplification. Sixty formalin-fixed paraffin-embedded specimens from metastatic CRC were analyzed for K-Ras mutations by using both SS and PS and results and compared with PNA-directed PCR clamping method. Sensitivity was tested performing serial dilutions with plasmids carrying either wt or mutated sequences. Results PNA-methods displayed higher sensitivity compared to both SS and PS, allowing mutations detection up to 98.5%. The results showed a concordance of 63.3% among the three methods, while the concordance between PS and PNA-method resulted significantly increased. 47 samples were found to be mutated by PNA-PCR clamping, while 30 and 26 by PS and SS, respectively. Major discrepancy (13 out of 14) regards the detection of mutations by PNA-methods, otherwise unidentified either by SS or PS. Four samples, previously fallen into grey area, were classified as mutated by PNA-method. PNA-method failed to detect mutations just in 1 out of 30 cases, thus displaying a specificity of 96.66%. Correlation between clinical outcome after Cetuximab treatment and genotyping by PNA-method, which will confirm the clinical usefulness of the new method, is ongoing. Conclusion We developed an innovative method, able to detect K-Ras mutations in tumor paraffin-embedded specimens with very high sensitivity (98.5%). This is a cheap, easy to apply, quick and sensitive technique that could represent a novel tool, useful in clinical practice to drive therapeutic decisions.