Targeted sequencing of cancer-related genes reveals a recurrent TOP2A variant which affects DNA binding and coincides with global transcriptional changes in glioblastoma.

High-grade gliomas are aggressive, deadly primary brain tumors. Median survival of patients with glioblastoma (GBM, WHO grade 4) is 14 months and <10% of patients survive 2 years. Despite improved surgical strategies and forceful radiotherapy and chemotherapy, the prognosis of GBM patients is poor and did not improve over decades. We performed targeted next-generation sequencing with a custom panel of 664 cancer- and epigenetics-related genes, and searched for somatic and germline variants in 180 gliomas of different WHO grades. Herein, we focus on 135 GBM IDH-wild type samples. In parallel, mRNA sequencing was accomplished to detect transcriptomic abnormalities. We present the genomic alterations in high-grade gliomas and the associated transcriptomic patterns. Computational analyses and biochemical assays showed the influence of TOP2A variants on enzyme activities. In 4/135 IDH-wild type GBMs we found a novel, recurrent mutation in the TOP2A gene encoding topoisomerase 2A (allele frequency [AF] = 0.03, 4/135 samples). Biochemical assays with recombinant, wild type (WT) and variant proteins demonstrated stronger DNA binding and relaxation activity of the variant protein. GBM patients carrying the altered TOP2A had shorter overall survival (median OS 150 vs 500 days, P = .0018). In the GBMs with the TOP2A variant we found transcriptomic alterations consistent with splicing dysregulation. luA novel, recurrent TOP2A mutation, which was found exclusively in four GBMs, results in the TOP2A E948Q variant with altered DNA binding and relaxation activities. The deleterious TOP2A mutation resulting in transcription deregulation in GBMs may contribute to disease pathology.

NGS-based targeted sequencing identified two novel variants in Southwestern Chinese families with oculocutaneous albinism.

BACKGROUND: Oculocutaneous albinism (OCA) is a group of heterogeneous genetic diseases characterized by a reduction or complete lack of pigmentation in the hair, skin, and eyes. It is associated with reduced visual acuity, nystagmus, photophobia, and strabismus. OCA type 1 (OCA1) and type 2 (OCA2) are caused by mutations in the tyrosinase (TYR) and OCA2 genes, which are responsible for most cases of OCA. The present study aimed to identify the mutational spectra of 18 southwest Chinese probands with OCA. RESULTS: We used a skin disease-targeted panel to sequence more than 400 genes, including 23 genes (TYR, OCA2, AP3B1, BLOC1S3, BLOC1S6, C10orf11, DTNBP1, FRMD7, GPR143, HPS1, HPS3, HPS4, HPS5, HPS6, LYST, MC1R, MITF, MLPH, MYO5A, RAB27A, SLC24A5, SLC45A2, TYRP1) associated with syndromic and non-syndromic albinism. The targeted panel was applied to 18 patients from southwest China, nine (50%) patients were diagnosed with OCA1, and nine (50%) were diagnosed with OCA2. Our data indicate that OCA1 and OCA2, the most common subtypes, probably have the same prevalence in southwest China. In total, we identified 26 variants in TYR and OCA2 from 18 OCA cases using the NGS technology, including 24 variants presented in the Human Gene Mutation Database Professional (HGMD) and two novel variants, c.559_560insCATTATTATGTGTCAAATTATCCCC in TYR and c.1514 T > C in OCA2, which have not been previously reported. According to the American College of Medical Genetics and Genomics (ACMG) classification, c.559_560insCATTATTATGTGTCAAATTATCCCC (p.G190Cfs*12) is classified as a pathogenic variant, and c.1514 T > C (p.F505S) is evaluated as a likely pathogenic variant. CONCLUSIONS: Two novel variants were identified which will expand the mutational spectra of TYR and OCA2. The results of the present study may have implications for genetic counseling, carrier screening, and clinical management of the disease.

Serial circulating tumor DNA monitoring of CDK4/6 inhibitors response in metastatic breast cancer.

Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) significantly improve progression-free survival and have become the standard therapy for estrogen receptor-positive/human epidermal growth factor receptor 2-negative metastatic breast cancer patients. Treatment surveillance by radiological imaging has some limitations in detection and repeated biopsy genomic profiling is not clinically feasible. Serial circulating tumor DNA (ctDNA) analysis may provide insights into treatment response. Here we performed serial ctDNA analysis (n = 178) on 33 patients. Serial ctDNA analysis identified disease progression with sensitivity of 75% and specificity of 92%. In eight of 12 patients (61%) responding to CDK4/6i who eventually developed progressive disease, serial sampling every 3 or 6 months captured the initial rise of ctDNA with an average lead time of 3 months. In three of eight patients that did not respond to CDK4/6i (progressive disease at first radiological assessment, 3 months), biweekly sequencing within the first cycle of CDK4/6i treatment (1 month) detected sustained ctDNA levels (≥0.2% variant allele frequency), with lead time of 2 months. Serial ctDNA analysis tracked RECIST response, including clinically challenging scenarios (bone metastases or small-sized target lesions), as well as detecting acquired genetic alterations linked to CDK4/6i resistance in the G1 to S transition phase. Circulating tumor DNA analysis was more sensitive than carcinoembryonic antigen or cancer antigen 15-3 serum tumor markers at monitoring tumor response to CDK4/6i treatment. Our findings indicated the possible clinical utility of serial ctDNA analysis for earlier progressive disease detection and real-time monitoring of CDK4/6i response.

Molecular diagnosis in a cohort of 114 patients with rare skeletal dysplasias.

Molecular diagnosis is important to provide accurate genetic counseling of skeletal dysplasias (SD). Although next-generation sequencing (NGS) techniques are currently the preferred methods for analyzing these conditions, some of the published results have not shown a detection rate as high as it would be expected. The present study aimed to assess the diagnostic yield of targeted NGS combined with Sanger sequencing (SS) for low-coverage exons of genes of interest and exome sequencing (ES) in a series of patients with rare SD and use two patients as an example of our strategy. This study used two different in-house panels. Of 93 variants found in 88/114 (77%) patients, 57 are novel. The pathogenic variants found in the following genes: B3GALT6, PCYT1A, INPPL1, LIFR, of four patients were only detected by SS. In conclusion, the high diagnostic yield reached in the present study can be attributed to both a good selection of patients and the utilization of the SS for the insufficiently covered regions. Additionally, the two case reports-a patient with acrodysostosis related to PRKAR1A and another with ciliopathy associated with KIAA0753, add new and relevant clinical information to the current knowledge.

Novel familial IQSEC2 pathogenic sequence variant associated with neurodevelopmental disorders and epilepsy.

Pathogenic sequence variants in the IQ motif- and Sec7 domain-containing protein 2 (IQSEC2) gene have been confirmed as causative in the aetiopathogenesis of neurodevelopmental disorders (intellectual disability, autism) and epilepsy. We report on a case of a family with three sons; two of them manifest delayed psychomotor development and epilepsy. Initially proband A was examined using a multistep molecular diagnostics algorithm, including karyotype and array-comparative genomic hybridization analysis, both with negative results. Therefore, probands A and B and their unaffected parents were enrolled for an analysis using targeted "next-generation" sequencing (NGS) with a gene panel ClearSeq Inherited DiseaseXT (Agilent Technologies) and verification analysis by Sanger sequencing. A novel frameshift variant in the X-linked IQSEC2 gene NM_001111125.2:c.1813_1814del, p.(Asp605Profs*3) on protein level, was identified in both affected probands and their asymptomatic mother, having skewed X chromosome inactivation (XCI) (100:0). As the IQSEC2 gene is a known gene escaping from XCI in humans, we expect the existence of mechanisms maintaining the normal or enough level of the IQSEC2 protein in the asymptomatic mother. Further analyses may help to the characterization of the presented novel frameshift variant in the IQSEC2 gene as well as to elucidate the mechanisms leading to the rare asymptomatic phenotypes in females.

A novel delins (c.773_819+47delinsAA) mutation of the PCCA gene associated with neonatal-onset propionic acidemia: a case report.

BACKGROUND: Propionic acidemia (PA)(OMIM#606054) is an inborn error of branched-chain amino acid metabolism, caused by defects in the propionyl-CoA carboxylase (PCC) enzyme which encoded by the PCCA and PCCB genes. CASE PRESENTATION: Here we report a Chinese neonate diagnosed with suspected PA based on the clinical symptoms, gas chromatography-mass spectrometry (GC/MS), and brain imaging tests. Targeted next-generation sequencing (NGS) was performed on the proband. We detected only one heterozygous recurrent nonsense variant (c.937C > T, p.Arg313Ter) in the PCCA gene. When we manually checked the binary alignment map (BAM) diagram of PCCA gene, we found a heterozygous deletion chr13:100915039-100915132delinsAA (c.773_819 + 47delinsAA) (GRCh37.p13) inside the exon 10 in the PCCA gene. The results were validated by Sanger sequencing and qPCR method in the family: the variant (c.937C > T, p.Arg313Ter) was in the maternal allele, and the delins was in the paternal allele. When the mother was pregnant again, prenatal diagnosis was carried out through amniocentesis at 18 weeks gestation, the fetus carried neither of the two mutations. After birth, newborn screening was undertaken, the result was negative. CONCLUSIONS: We identified a recurrent c.937C > T and a novel c.773_819 + 47delinsAA mutations in the PCCA gene, which may be the genetic cause of the phenotype of this patient. Our findings expanded the spectrum of causative genotype-phenotype of the PCCA gene. For the cases, the NGS results revealed only a heterozygous mutation in autosomal recessive disease when the gene is associated with phenotypes, it is necessary to manually check the BAM diagram to improve the detection rate. Targeted NGS is an effective technique to detect the various genetic lesions responsible for the PA in one step. Genetic testing is essential for genetic counselling and prenatal diagnosis in the family to avoid birth defects.

Indian child with novel variant in OFD1 gene.

Orofaciodigital syndrome (OFD) can have variable phenotype and presents with oral anomalies, facial dysmorphism, and digital malformations like syndactyly, and polydactyly. Other presentations also include renal and cardiac defects, and central nervous system anomalies like hydrocephalus and cerebellar abnormalities. OFD1 is a X-linked dominant form of the syndrome presenting in females with mutations in CXorf5 or OFD1 gene. We describe a young child with sparse hairs, milia over face and absence of corpus callosum. Next generation sequencing showed frameshift pathogenic variant in the exon 13 of the OFD1 gene, consistent with diagnosis of OFD1.

Characterization of a Novel 71.8 kb α0-Thalassemia Deletion and Subsequent Summary of a Practical Procedure for Thalassemia Molecular Diagnosis.

Thalassemia is the most common monogenic disorder around the world. Based on the principle of genotype-phenotype correlation, identification of thalassemia mutations is the essential prerequisite for clinical diagnosis and management. Because only common mutations are routinely detected, the identification of rare or undetermined mutations is a challenge for clinical laboratories. Herein, a proband presenting with inconsistent phenotype-genotype correlation after routine molecular screening was investigated by multiplex ligation-dependent probe amplification (MLPA), targeted-next generation sequencing (targeted-NGS), gap-polymerase chain reaction (gap-PCR) and Sanger sequencing. Eventually, a novel 71.8 kb deletion (- -71.8) was identified and characterized, which included HBZ (ζ), HBA2 (α2), and HBA1 (α1) genes and was causing α0-thalassemia (α0-thal). Furthermore, we summarized a practical procedure based on accumulated experience in studies and clinical practice, which can be a guide for molecular screening and clinical diagnosis of thalassemia, especially for identification of undetermined or novel mutations.

Novel compound heterozygous mutations in OCA2 gene associated with non-syndromic oculocutaneous albinism in a Chinese Han patient: a case report.

BACKGROUND: Oculocutaneous albinism (OCA) is a group of rare genetically heterogeneous disorders. The present study aimed to identify the genetic cause of a Chinese Han family with non-syndromic oculocutaneous albinism (OCA). CASE PRESENTATION: Here, we report an 11-month-old male proband from a Chinese Han non-consanguineous family, who presented with milky skin, yellow white hair, nystagmus, astigmatism, and hypermetropia. We performed the targeted next-generation sequencing (NGS) on the proband and identified two novel compound heterozygous variants (c.1865 T > C (p.Leu622Pro) and exons 17-21 deletion) in OCA2 gene associated with OCA type 2 (OCA2, OMIM 203200). Meanwhile, a previously reported heterozygous mutation (c.4805G > A) in MYO7 gene related with Usher syndrome type 1B was found. The online tools SIFT, PolyPhen-2, and Mutation Taster predicted variant c.1865 T > C was probably damaging. The residue p.Leu622 was in a highly conserved region among species by CLUSTALW. Three-dimensional homology model with I-TASSER indicated that p.Leu622Pro variant disturbed the formation of the α-helix, resulting in a random coil structure. The gross deletion (exons 17-21) in OCA2 gene has was not been reported previously. These two novel variants in OCA2 gene were inherited from each parent respectively, after verification by Sanger sequencing and quantitative PCR (qPCR) in the family. CONCLUSIONS: This study indicates the two novel compound heterozygous mutations in OCA2 gene may be responsible for clinical manifestations of OCA2. It expands the mutation spectrum of OCA2 gene and is helpful to screen for large deletions with targeted NGS protocol in monogenic disease. It also assists the genetic counselling, carrier screening and personalized healthcare of the disease.

Targeted next-generation sequencing identifies clinically relevant somatic mutations in a large cohort of inflammatory breast cancer.

BACKGROUND: Inflammatory breast cancer (IBC) is the most aggressive form of primary breast cancer. Using a custom-made breast cancer gene sequencing panel, we investigated somatic mutations in IBC to better understand the genomic differences compared with non-IBC and to consider new targeted therapy in IBC patients. METHODS: Targeted next-generation sequencing (NGS) of 91 candidate breast cancer-associated genes was performed on 156 fresh-frozen breast tumor tissues from IBC patients. Mutational profiles from 197 primary breast tumors from The Cancer Genome Atlas (TCGA) were used as non-IBC controls for comparison analysis. The mutational landscape of IBC was correlated with clinicopathological data and outcomes. RESULTS: After genotype calling and algorithmic annotations, we identified 392 deleterious variants in IBC and 320 variants in non-IBC cohorts, respectively. IBC tumors harbored more mutations than non-IBC (2.5 per sample vs. 1.6 per sample, p < 0.0001). Eighteen mutated genes were significantly different between the two cohorts, namely TP53, CDH1, NOTCH2, MYH9, BRCA2, ERBB4, POLE, FGFR3, ROS1, NOTCH4, LAMA2, EGFR, BRCA1, TP53BP1, ESR1, THBS1, CASP8, and NOTCH1. In IBC, the most frequently mutated genes were TP53 (43.0%), PIK3CA (29.5%), MYH9 (8.3%), NOTCH2 (8.3%), BRCA2 (7.7%), ERBB4 (7.1%), FGFR3 (6.4%), POLE (6.4%), LAMA2 (5.8%), ARID1A (5.1%), NOTCH4 (5.1%), and ROS1 (5.1%). After grouping 91 genes on 10 signaling pathways, we found that the DNA repair pathway for the triple-negative breast cancer (TNBC) subgroup, the RTK/RAS/MAPK and cell cycle pathways for the HR-/HER2+ subgroup, the DNA repair, RTK/RAS/MAPK, and NOTCH pathways for the HR+/HER2- subgroup, and the DNA repair, epigenome, and diverse pathways for the HR+/HER2+ subgroup were all significantly differently altered between IBC and non-IBC. PIK3CA mutation was independently associated with worse metastasis-free survival (MFS) in IBC since the median MFS for the PIK3CA mutant type was 26.0 months and for the PIK3CA wild type was 101.1 months (p = 0.002). This association was observed in TNBC (p = 0.04) and the HR-/HER2+ subgroups (p = 0.0003), but not in the HR+/HER2- subgroup of IBC. CONCLUSIONS: Breast cancer-specific targeted NGS uncovered a high frequency of deleterious somatic mutations in IBC, some of which may be relevant for clinical management.

Genetic diagnosis of neurofibromatosis type 1: targeted next- generation sequencing with Multiple Ligation-Dependent Probe Amplification analysis.

BACKGROUND: Neurofibromatosis type 1 (NF1) is a dominantly inherited tumor predisposition syndrome that targets the peripheral nervous system. It is caused by mutations of the NF1 gene which serve as a negative regulator of the cellular Ras/MAPK (mitogen-activated protein kinases) signaling pathway. Owing to the complexity in some parts of clinical diagnoses and the need for better understanding of its molecular relationships, a genetic characterization of this disorder will be helpful in the clinical setting. METHODS: In this study, we present a customized targeted gene panel of NF1/KRAS/BRAF/p53 and SPRED1 genes combined with Multiple Ligation-Dependent Probe Amplification analysis for the NF1 mutation screening in a cohort of patients clinically suspected as NF1. RESULTS: In this study, we identified 73 NF1 mutations and two BRAF novel variants from 100 NF1 patients who were suspected as having NF1. These genetic alterations are heterogeneous and distribute in a complicated way without clustering in either cysteine-serine-rich domain or within the GAP-related domain. We also detected fifteen multi-exon deletions within the NF1 gene by MLPA Analysis. CONCLUSIONS: Our results suggested that a genetic screening using a NGS panel with high coverage of Ras-signaling components combined with Multiple Ligation-Dependent Probe Amplification analysis will enable differential diagnosis of patients with overlapping clinical features.

Identification of Three Novel Frameshift Mutations in the PKD1 Gene in Iranian Families with Autosomal Dominant Polycystic Kidney Disease Using Efficient Targeted Next-Generation Sequencing.

BACKGROUND/AIMS: Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common inherited cystic kidney diseases caused by mutations in two large multi-exon genes, PKD1 and PKD2. High allelic heterogeneity and duplication of PKD1 exons 1-32 as six pseudo genes on chromosome 16 complicate molecular analysis of this disease. METHODS: We applied targeted next-generation sequencing (NGS) in 9 non-consanguineous unrelated Iranian families with ADPKD to identify the genes hosting disease-causing mutations. This approach was confirmed by Sanger sequencing. RESULTS: Here, we determined three different novel frameshift mutations and four previously reported nonsense mutations in the PKD1 gene encoding polycystin1 in heterozygotes. CONCLUSION: This study demonstrates the effectiveness of NGS in significantly reducing the cost and time for simultaneous sequence analysis of PKD1 and PKD2, simplifying the genetic diagnostics of ADPKD. Although a probable correlation between the mutation types and phenotypic outcome is possible, however for more extensive studies in future, the consideration of renal hypouricemia (RHUC) and PKD1 coexistence may be helpful. The novel frameshift mutations reported by this study are p. Q1997X, P. D73X and p. V336X.

A novel pathogenic frameshift variant of CD3E gene in two T-B+ NK+ SCID patients from Turkey.

Severe combined immunodeficiency (SCID) is the most severe form of primary immunodeficiency, which is characterized by the dysfunction and/or absence of T lymphocytes. Early diagnosis of SCID is crucial for overall survival, and if it remains untreated, SCID is often fatal. Next-generation sequencing (NGS) has become a rapid, high-throughput technology, and has already been proven to be beneficial in medical diagnostics. In this study, a targeted NGS panel was developed to identify the genetic variations of SCID by using SmartChip-TE technology, and a novel pathogenic frameshift variant was found in the CD3E gene. Sanger sequencing has confirmed the segregation of the variant among patients. We found a novel deletion in the CD3E gene (NM000733.3:p.L58Hfs*9) in two T-B+ NK+ patients. The variant was not found in the databases of dbSNP, ExAC, and 1000G. One sibling in family I was homozygous and the rest of the family members were heterozygous for this variant. T cell receptor excision circle (TREC) and kappa-deleting recombination excision circle (KREC) analyses were performed for T and B cell maturation. TRECs were not detected in both patients and the KREC copy numbers were similar to the other family members. In addition, heterozygous family members showed decreased TREC levels when compared with the wild-type sibling, indicating that carrying this variant in one allele does not cause immunodeficiency, but does effect T cell proliferation. Here, we report a novel pathogenic frameshift variant in CD3E gene by using targeted NGS panel.

Chondrodysplasia with multiple dislocations: comprehensive study of a series of 30 cases.

The group of chondrodysplasia with multiple dislocations includes several entities, characterized by short stature, dislocation of large joints, hand and/or vertebral anomalies. Other features, such as epiphyseal or metaphyseal changes, cleft palate, intellectual disability are also often part of the phenotype. In addition, several conditions with overlapping features are related to this group and broaden the spectrum. The majority of these disorders have been linked to pathogenic variants in genes encoding proteins implicated in the synthesis or sulfation of proteoglycans (PG). In a series of 30 patients with multiple dislocations, we have performed exome sequencing and subsequent targeted analysis of 15 genes, implicated in chondrodysplasia with multiple dislocations, and related conditions. We have identified causative pathogenic variants in 60% of patients (18/30); when a clinical diagnosis was suspected, this was molecularly confirmed in 53% of cases. Forty percent of patients remain without molecular etiology. Pathogenic variants in genes implicated in PG synthesis are of major importance in chondrodysplasia with multiple dislocations and related conditions. The combination of hand features, growth failure severity, radiological aspects of long bones and of vertebrae allowed discrimination among the different conditions. We propose key diagnostic clues to the clinician.

Evaluation of bacterial pathogen diversity, abundance and health risks in urban recreational water by amplicon next-generation sequencing and quantitative PCR.

The microbial quality of urban recreational water is of great concern to public health. The monitoring of indicator organisms and several pathogens alone is not sufficient to accurately and comprehensively identify microbial risks. To assess the levels of bacterial pathogens and health risks in urban recreational water, we analyzed pathogen diversity and quantified four pathogens in 46 water samples collected from waterbodies in Beijing Olympic Forest Park in one year. The pathogen diversity revealed by 16S rRNA gene targeted next-generation sequencing (NGS) showed that 16 of 40 genera and 13 of 76 reference species were present. The most abundant species were Acinetobacter johnsonii, Mycobacterium avium and Aeromonas spp. Quantitative polymerase chain reaction (qPCR) of Escherichia coli (uidA), Aeromonas (aerA), M. avium (16S rRNA), Pseudomonas aeruginosa (oaa) and Salmonella (invA) showed that the aerA genes were the most abundant, occurring in all samples with concentrations of 104-6 genome copies/100mL, followed by oaa, invA and M. avium. In total, 34.8% of the samples harbored all genes, indicating the prevalence of these pathogens in this recreational waterbody. Based on the qPCR results, a quantitative microbial risk assessment (QMRA) showed that the annual infection risks of Salmonella, M. avium and P. aeruginosa in five activities were mostly greater than the U.S. EPA risk limit for recreational contacts, and children playing with water may be exposed to the greatest infection risk. Our findings provide a comprehensive understanding of bacterial pathogen diversity and pathogen abundance in urban recreational water by applying both NGS and qPCR.

Mutational Spectrum in Holoprosencephaly Shows That FGF is a New Major Signaling Pathway.

Holoprosencephaly (HPE) is the most common congenital cerebral malformation in humans, characterized by impaired forebrain cleavage and midline facial anomalies. It presents a high heterogeneity, both in clinics and genetics. We have developed a novel targeted next-generation sequencing (NGS) assay and screened a cohort of 257 HPE patients. Mutations with high confidence in their deleterious effect were identified in approximately 24% of the cases and were held for diagnosis, whereas variants of uncertain significance were identified in 10% of cases. This study provides a new classification of genes that are involved in HPE. SHH, ZIC2, and SIX3 remain the top genes in term of frequency with GLI2, and are followed by FGF8 and FGFR1. The three minor HPE genes identified by our study are DLL1, DISP1, and SUFU. Here, we demonstrate that fibroblast growth factor signaling must now be considered a major pathway involved in HPE. Interestingly, several cases of double mutations were found and argue for a polygenic inheritance of HPE. Altogether, it supports that the implementation of NGS in HPE diagnosis is required to improve genetic counseling.

Effective variant detection by targeted deep sequencing of DNA pools: an example from Parkinson's disease.

Next-generation sequencing technologies will dominate the next phase of discoveries in human genetics, but considerable costs may still represent a limitation for studies involving large sample sets. Targeted capture of genomic regions may be combined with deep sequencing of DNA pools to efficiently screen sample cohorts for disease-relevant mutations. We designed a 200 kb HaloPlex kit for PCR-based capture of all coding exons in 71 genes relevant to Parkinson's disease and other neurodegenerative disorders. DNA from 387 patients with Parkinson's disease was combined into 39 pools, each representing 10 individuals, before library preparation with barcoding and Illumina sequencing. In this study, we focused the analysis on six genes implicated in Mendelian Parkinson's disease, emphasizing quality metrics and evaluation of the method, including validation of variants against individual genotyping and Sanger sequencing. Our data showed 97% sensitivity to detect a single nonreference allele in pools, rising to 100% where pools achieved sequence depth above 80x for the relevant position. Pooled sequencing detected 18 rare nonsynonymous variants, of which 17 were validated by independent methods, corresponding to a specificity of 94%. We argue that this design represents an effective and reliable approach with possible applications for both complex and Mendelian genetics.

Novel pathogenic COL11A1/COL11A2 variants in Stickler syndrome detected by targeted NGS and exome sequencing.

INTRODUCTION: Stickler syndrome is caused by mutations in genes encoding type II and type XI collagens. About 85% of the pathogenic variants is found in COL2A1 (Stickler type 1), whereas a minority of mutations has been reported in COL11A1 (Stickler type 2) and COL11A2 (Stickler type 3). Beside the typical skeletal and orofacial manifestations, ocular anomalies are predominantly present in type 1 and type 2, while hearing loss is more pronounced in type 2 and type 3. METHODS: We performed COL11A1 mutation analysis for 40 type 2 Stickler patients and COL11A2 mutation analysis for five type 3 Stickler patients, previously all COL2A1 mutation-negative, using targeted next-generation sequencing (NGS) whereas whole-exome sequencing (WES) was performed in parallel for two patients. Three patients were analyzed for both genes due to unclear ocular findings. RESULTS: In total 14 COL11A1 and two COL11A2 mutations could be identified, seven of which are novel. Splice site alterations are the most frequent mutation type, followed by glycine substitutions. In addition, six variants of unknown significance (VUS) have been found. Identical mutations and variants were identified with both NGS techniques. CONCLUSION: We expand the mutation spectrum of COL11A1 and COL11A2 in Stickler syndrome patients and show that targeted NGS is an efficient and cost-effective molecular tool in the genetic diagnosis of Stickler syndrome, whereas the more standardized WES might be an alternative approach.

Targeted next-generation sequencing assay to detect 3 Moraxella spp. directly from bovine ocular swabs.

Infectious bovine keratoconjunctivitis (IBK) is associated with 2 species of Moraxella: M. bovis and M. bovoculi. A third novel Moraxella spp., designated tentatively as M. oculi, has been identified from the eyes of cattle with and without pinkeye. These 3 Moraxella spp. can be found in various combinations within the same clinical sample, making speciation of this genus directly from a sample impossible with Sanger sequencing. Assessing Moraxella diversity found in IBK- and non-IBK-affected cattle eyes, independent of culture, may provide additional information about IBK by avoiding the selectivity bias of culturing. We developed a targeted NGS panel to detect and speciate these 3 Moraxella spp. directly from bovine ocular swabs. Our targeted panel amplifies bacterial essential genes and the 16S-23S ribosomal RNA intergenic spacer region (ITS) of the 3 Moraxella spp. and speciates based on these sequences. Our panel was able to differentiate the 3 species directly from DNA extracted from 13 swabs (6 from healthy animals, 7 from animals with IBK), and every swab except one (clinically healthy eye) had the 3 Moraxella spp. Targeted NGS with sequencing of Moraxella spp. housekeeping genes appears to be a suitable method for speciation of Moraxella directly from ocular swabs.

Targeted Next Generation Sequencing molecular profiling and its clinical application in adrenocortical cancer.

OBJECTIVE: Adrenal cortical carcinoma (ACC) is a rare malignancy with a generally poor but heterogeneous prognosis, especially depending on the tumour stage at diagnosis. Identification of somatic gene alterations combined with clinical/histopathological evaluation of the tumour can help improve prognostication. We applied a simplified targeted-Next-Generation Sequencing (NGS) panel to characterise the mutational profiles of ACCs, providing potentially relevant information for better patient management. DESIGN AND METHODS: Thirty frozen tumour specimens from a local ACC series were retrospectively analysed by a custom-NGS panel (CDKN2A, CTNNB1, DAXX, MED12, NF1, PRKAR1A, RB1, TERT, TP53, ZNRF3) to detect somatic prioritised single-nucleotide variants. This cohort was integrated with 86 patients from the ACC-TCGA series bearing point-mutations in the same genes and their combinations identified by our panel. Primary endpoints of the analysis on the total cohort (113 patients) were overall survival (OS) and progression-free survival (PFS), and hazard ratio (HR) for the different alterations grouped by the signalling pathways/combinations affected. RESULTS: Different PFS, OS, and HR were associated to the different pathways/combinations, being NF1 + TP53 and Wnt/ß-catenin + Rb/p53 combined mutations the most deleterious, with a statistical significance for progression HR which is retained only in low-(I/II) stages-NF1 + TP53 combination: HR = 2.96[1.01-8.69] and HR = 13.23[3.15-55.61], all and low stages, respectively; Wnt/ß-catenin + Rb/p53 combined pathways: HR = 6.47[2.54-16.49] and HR = 16.24[3.87-68.00], all and low-stages, respectively. CONCLUSIONS: A simplified targeted-NGS approach seems the best routinely applicable first step towards somatic genetic characterisation of ACC for prognostic assessment. This approach proved to be particularly promising in low-stage cases, suggesting the need for more stringent surveillance and personalised treatment.