Until recently, the molecular diagnosis of hereditary breast and ovarian cancer (HBOC) was mostly based on BRCA1/2 testing. Next generation sequencing and the recent discovery of new genes involved in HBOC now permit the transfer of genomic capture targeting multiple candidate genes from research to clinical use. However, the implications for the management of patients and their families have not been extensively studied, in particular since some of these genes are not well-established cancer predisposing genes. We studied 583 consecutive patients from Burgundy (France) fulfilling the criteria for BRCA testing using a next generation sequencing 25-genes panel including 20 well-established high-risk cancer genes as well as more recently identified predisposing HBOC cancer. A pathogenic BRCA1/2 mutation was found in 51 patients (9%). Besides, we found 37 pathogenic or likely pathogenic mutations in 10 different high to low-risk genes in 34 patients (6%). The most frequently mutated genes were CHEK2 (n = 12; 2%), ATM (n = 9; 1.5%), and PALB2 (n = 4; 0.6%). Three patients had a mutation in two different predisposing genes. The analysis of clinical actionability conducted in mutation-positive individuals revealed that additional disease-specific screening and/or prevention measures beyond those based on personal and family history alone had been recommended in 69% of cases. In conclusion, multigene panel testing is a powerful tool to identifying high to low-risk HBOC susceptibility genes. The penetrance and spectrum of cancers with these other genes are sometimes undefined, and further collaborative work is crucial to address this question.

BackgroundPrader-Willi syndrome (PWS) is characterized by hypotonia, delayed neuropsychomotor development, overeating, obesity and mental deficiency. This phenotype is encountered in other conditions, defining Prader-Willi-like syndrome (PWLS).Case presentationWe report a 14-year-old boy with a complex small supernumerary marker chromosome (sSMC) associated with PWLS. The propositus presents clinical features commonly found in patients with PWLS, including growth hormone deficit. Banding karyotype analysis and fluorescence in situ hybridization (FISH) revealed a marker derived from chromosome 6 and a neocentromere as suspected, but array-CGH enabled us to characterize this marker as a der(10)t(6;10)(6qter → 6q23.3::10p11.1 → 10p11.21)dn. As far as we know, this is the first diagnosed case of PWLS associated with a complex sSMC, involving a 30.9 Mb gain in the 6q16.3q23.3 region and a 3.5 Mb gain in the 10p11.21p11.1 region. Several genes have been mapped to the 6q region including the TCBA1 gene, which is associated with developmental delay and recurrent infections, the ENPP1 gene, associated with insulin resistance and susceptibility to obesity and the BMIQ3 gene, associated with body mass index (BMI). No OMIM gene was found in the smallest 10p11.21p11.1 region.ConclusionsWe suggest that the duplicated chromosome segment 6q16.3q23.3 may be responsible for the phenotype of our case and may also be a candidate locus of PWLS.

Background : Most cases of breast and ovarian cancer susceptibility remains unexplained. Testing multiple genes in one go with next generation sequencing is then an asset with the recent discovery of new genes involved in breast and ovarian cancer susceptibility. Methods : We studied 457 patients originated from Burgundy (France) fulfilling the criteria for BRCA1/2 testing using a next generation sequencing 25-gene panel including 17 genes of predisposition for breast and/or ovarian cancer (ATM, BARD1, BRCA 1/2, BRIP1, CHEK2, PALB2, RAD51C, TP53, PTEN, RAD50, MRE11, MLH1, MSH2, MSH6, PMS2, STK11). Results : A pathogenic BRCA1/2 mutation was found in 8% (n=37) of patients. Besides, we found 39 deleterious or probably deleterious mutations in 13 different genes. The most frequently mutated genes were CHEK2 (n=10 ; 2.1 %), ATM (n=9 ; 2 %), and PALB2 (n=4 ; 0.9%). One patient had deleterious mutations in both TP53 and PALB2, and another one had deleterious mutations in both BRCA2 and CHEK2. The mutation could explain the phenotype in the majority of cases, but a pathogenic mutation was found in a different predisposing gene in 7 patients, and could be considered as incidental findings with the currently published spectrum of cancer locations. Conclusion : Besides BRCA1/2 mutations, that remain the most frequent susceptibility genes for breast and ovarian cancer, gene panels remain a powerful tool for identifying the other less frequent susceptibility genes. The penetrance and spectrum of cancer associated to these other genes remain sometimes undefined, and further collaborative work is crucially needed to address this question. The possibility of double hits should led to careful genetic counseling. Citation Format: Eliade M, Skrypski J, Baurand A, Jacquot C, Bertolone G, Loustalot C, Coutant C, Guy F, Fumoleau P, Rivière J-B, Duffourd Y, Ghiringhelli F, Végran F, Boidot R, Lizard S, Faivre L. The power of next generation sequencing in the detection of breast and ovarian cancer susceptibility genes other than BRCA. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-06-04.

Until recently, the molecular diagnosis of hereditary breast and ovarian cancer (HBOC) was mostly based on BRCA1/2 testing. Next generation sequencing and the recent discovery of new genes involved in HBOC now permit the transfer of genomic capture targeting multiple candidate genes from research to clinical use. However, the implications for the management of patients and their families have not been extensively studied, in particular since some of these genes are not well-established cancer predisposing genes. We studied 583 consecutive patients from Burgundy