Additional Copy Number Variants Research Articles

Aneuploid embryonic stem cells drive teratoma metastasis

Aneuploidy, a deviation of the chromosome number from euploidy, is one of the hallmarks of cancer. High levels of aneuploidy are generally correlated with metastasis and poor prognosis in cancer patients. However, the causality of aneuploidy in cancer metastasis remains to be explored. Here we demonstrate that teratomas derived from aneuploid murine embryonic stem cells (ESCs), but not from isogenic diploid ESCs, disseminated to multiple organs, for which no additional copy number variations were required. Notably, no cancer driver gene mutations were identified in any metastases. Aneuploid circulating teratoma cells were successfully isolated from peripheral blood and showed high capacities for migration and organ colonization. Single-cell RNA sequencing of aneuploid primary teratomas and metastases identified a unique cell population with high stemness that was absent in diploid ESCs-derived teratomas. Further investigation revealed that aneuploid cells displayed decreased proteasome activity and overactivated endoplasmic reticulum (ER) stress during differentiation, thereby restricting the degradation of proteins produced from extra chromosomes in the ESC state and causing differentiation deficiencies. Noticeably, both proteasome activator Oleuropein and ER stress inhibitor 4-PBA can effectively inhibit aneuploid teratoma metastasis.

Genetic Characterization of Blood Group Antigens for Polynesian Heritage Norfolk Island Residents.

Improvements in blood group genotyping methods have allowed large scale population-based blood group genetics studies, facilitating the discovery of rare blood group antigens. Norfolk Island, an external and isolated territory of Australia, is one example of an underrepresented segment of the broader Australian population. Our study utilized whole genome sequencing data to characterize 43 blood group systems in 108 Norfolk Island residents. Blood group genotypes and phenotypes across the 43 systems were predicted using RBCeq. Predicted frequencies were compared to data available from the 1000G project. Additional copy number variation analysis was performed, investigating deletions outside of RHCE, RHD, and MNS systems. Examination of the ABO blood group system predicted a higher distribution of group A1 (45.37%) compared to group O (35.19%) in residents of the Norfolk Island group, similar to the distribution within European populations (42.94% and 38.97%, respectively). Examination of the Kidd blood group system demonstrated an increased prevalence of variants encoding the weakened Kidd phenotype at a combined prevalence of 12.04%, which is higher than that of the European population (5.96%) but lower than other populations in 1000G. Copy number variation analysis showed deletions within the Chido/Rodgers and ABO blood group systems. This study is the first step towards understanding blood group genotype and antigen distribution on Norfolk Island.

Large Chromosome 2p Duplication-Associated Mechanisms and Clinical Presentations

Chromosome 2p (chr2p) duplication, also known as trisomy 2p, is a rare chromosome abnormality associated with developmental delay, intellectual disability, behavioral problems, and distinctive facial features. Most of the reported cases involving trisomy 2p include additional copy number variants (CNVs) in other regions of the genome and are usually small in size. Little is known about the clinical outcomes of large duplications of chr2p as the sole cytogenetic abnormality. In this study, 193 samples at the Greenwood Genetic Center (GGC) with CNVs involving chr2p were evaluated, out of which 86 had chr2p duplications. Among them, 8 patients were identified with large chr2p duplications ranging in size from 9.3 Mb to 89 Mb, and no deletions or duplications involving other chromosomes were identified in those patients. These duplications were associated with inverted duplication, tandem duplication, and duplication as the result of translocation, with no additional CNVs identified by microarray analysis. Confirmation by conventional cytogenetics was performed in 7 of the 8 patients, and the translocations were confirmed by fluorescence in situ hybridization. Interestingly, 1 patient was found to have mosaic complete trisomy 2p as the result of an unbalanced de novo (X;2) chromosomal translocation. X-inactivation was skewed toward the derivative X chromosome, yet it did not appear to extend into the chromosome 2 material. Various shared clinical manifestations were observed in the individuals in this study, including developmental delay, hemifacial hypoplasia, cleft palate, and short stature, and they also have distinct features such as hypotonia, cerebellar hypogenesis, and corpus callosum agenesis, which might result from a gene dosage effect of the duplication. In conclusion, single-event large chr2p duplications can result from different mechanisms, including inverted or tandem duplications within chromosome 2, or translocations involving chromosome 2 and other chromosomes. Partial or complete trisomy 2p is commonly associated with developmental delay, and additional clinical features may be related to gene dosage effects.

Exome sequencing as first-tier genetic testing in infantile-onset pharmacoresistant epilepsy: diagnostic yield and treatment impact.

Pharmacoresistant epilepsy presenting during infancy poses both diagnostic and therapeutic challenges. We aim to identify diagnostic yield and treatment implications of exome sequencing (ES) as first-tier genetic testing for infantile-onset pharmacoresistant epilepsy. From June 2016 to December 2020, we enrolled patients with infantile-onset (age ≤ 12 months) pharmacoresistant epilepsy. 103 unrelated patients underwent ES. Clinical characteristics and changes in management due to the molecular diagnosis were studied. 42% (43/103) had epilepsy onset within the first month of life. After ES as first-tier genetic testing, 62% (64/103) of the cases were solved. Two partially solved cases (2%; 2/103) with heterozygous variants identified in ALDH7A1 known to cause autosomal recessive pyridoxine dependent epilepsy underwent genome sequencing (GS). Two novel large deletions in ALDH7A1 were detected in both cases. ES identified 66 pathogenic and likely pathogenic single nucleotide variants (SNVs) in 27 genes. 19 variants have not been previously reported. GS identified two additional copy number variations (CNVs). The most common disease-causing genes are SCN1A (13%; 13/103) and KCNQ2 (8%; 8/103). Eight percent (8/103) of the patients had treatable disorders and specific treatments were provided resulting in seizure freedom. Pyridoxine dependent epilepsy was the most common treatable epilepsy (6%; 6/103). Furthermore, 35% (36/103) had genetic defects which guided gene-specific treatments. Altogether, the diagnostic yield is 64%. Molecular diagnoses change management in 43% of the cases. This study substantiates the use of next generation sequencing (NGS) as the first-tier genetic investigation in infantile-onset pharmacoresistant epilepsy.

The successful strategy of comprehensive pre-implantation genetic testing for beta-thalassaemia–haemoglobin E disease and chromosome balance using karyomapping

Thalassaemia is the commonest monogenic disease and causes a health and economic burden worldwide. Karyomapping can be used for pre-implantation genetic testing of monogenic disorders (PGT-M). This study applied karyomapping in two PGT-M cycles and made a comparison to polymerase chain reaction (PCR). Two families at risk of having beta-thalassaemia–haemoglobin E disease offspring decided to join the project and informed consent was obtained. Karyomapping results of family A (beta-thalassaemia (c.41_42delTCTT)-Hb E (c.26G>A) disease) revealed four normal, two beta-thalassaemia traits, one Hb E trait and six affected. Three embryos exhibited unbalanced chromosomes. One normal male embryo was transferred. Karyomapping results of family B (beta-thalassaemia (c.17A>T)-Hb E (c.26G>A) disease) revealed six Hb E traits and three affected. Three embryos were chromosomally unbalanced. One Hb E trait embryo was transferred. Two successful karyomapping PGT-M were performed, including deletion and single-base mutations. Karyomapping provides accuracy as regards the protocol and copy number variation which is common in pre-implantation embryos. Impact Statement What is already known on this subject? Thalassaemia syndrome is the commonest monogenic disease and causes a health and economic burden worldwide. Modern haplotyping using SNP array (aSNP) and karyomapping algorithms can be used for pre-implantation genetic testing of monogenic disorders (PGT-M). However, few clinical karyomapping PGT-M cycles have been done and validated so far. What do the results of this study add? Two successful clinical PGT-M cycles for beta-thalassaemia (c.41_42delTCTT and c.17A>T mutations)–haemoglobin E (c.26G>A) disease were performed using karyomapping. The outcome was two healthy babies. Multiplex fluorescent polymerase chain reaction (PCR) with mini-sequencing was also used for confirmation mutation analysis results. PCR confirmed haplotyping results in all embryos. Six embryos from both PGT-M cycles exhibited unbalanced chromosomes evidenced by aSNP. What are the implications of these findings for clinical practice and/or further research? Karyomapping provides accurate information quickly and the outcomes of the study will save time as regards protocol development, provide a usable universal PGT-M protocol and add additional copy number variation (CNV) information, chromosome number variation being a common issue in pre-implantation embryos.

17. Chromosome 2p duplication associated mechanisms and clinical presentations

Chromosome 2p duplication, also known as trisomy 2p, is a rare chromosome abnormality, which is associated with developmental delay, intellectual disability, behavioral problems, and distinctive facial features. Most of the reported cases involving trisomy 2p include additional copy number variants in other regions of the genome and are usually small in size. Little is known about the clinical outcomes of large duplications of chromosome 2p alone. In this study, we analyzed 8 patients with large chromosome 2p duplications ranging in size from 9.3 Mb to 89 Mb. These duplications were identified in association with inverted duplication, tandem duplication, and duplication as the result of translocation, with no other copy number variant identified by microarray analysis. Seven out of 8 patients had confirmation by conventional cytogenetics and all of the translocations were confirmed by FISH. Interestingly, one case is a patient with mosaic complete trisomy 2p, who has a de novo (X;2) chromosomal translocation. X-inactivation was shown for the derivative X chromosome, yet it does not appear to extend into the chromosome 2 material. While patients share common clinical manifestations including developmental delay, hemifacial hypoplasia, cleft palate, and short stature, they also have distinct features such as hypotonia, cerebellar agenesis/hypogenesis, and corpus callosum agenesis, which might result from a gene dosage effect of the duplication. Triplosensitivity has been reported in patients with duplications covering 2p24.3 region. Global developmental delay and autism have also been reported in patients with de novo microduplications of 2p15p16.1. In conclusion, large chromosome 2p duplications could result from inverted or tandem duplications within chromosome 2, or translocations involving chromosome 2 and other chromosomes. Partial or complete trisomy 2p are commonly associated with developmental delay, and additional clinical features may be related to gene dosage effect.

Schizophrenia Risk Mediated by microRNA Target Genes Overlapped by Genome-Wide Rare Copy Number Variation in 22q11.2 Deletion Syndrome.

The 22q11.2 deletion is associated with >20-fold increased risk for schizophrenia. The presence of gene DGCR8 in the 22q11.2 deletion region has suggested microRNA (miRNA) dysregulation as possibly contributing to this risk. We therefore investigated the role of miRNA target genes in the context of previously identified genome-wide risk for schizophrenia conveyed by additional copy number variation (CNV) in 22q11.2 deletion syndrome (22q11.2DS). Using a cohort of individuals with 22q11.2DS and documented additional rare CNVs overlapping protein coding genes, we compared those with schizophrenia (n = 100) to those with no psychotic illness (n = 118), assessing for rare CNVs that overlapped experimentally supported miRNA target genes. We further characterized the contributing miRNA target genes using gene set enrichment analyses and identified the miRNAs most implicated. Consistent with our hypothesis, we found a significantly higher proportion of individuals in the schizophrenia than in the non-psychotic group to have an additional rare CNV that overlapped one or more miRNA target genes (odds ratio = 2.12, p = 0.0138). Gene set analyses identified an enrichment of FMRP targets and genes involved in nervous system development and postsynaptic density amongst these miRNA target genes in the schizophrenia group. The miRNAs most implicated included miR-17-5p, miR-34a-5p and miR-124-3p. These results provide initial correlational evidence in support of a possible role for miRNA perturbation involving genes affected by rare genome-wide CNVs in the elevated risk for schizophrenia in 22q11.2DS, consistent with the multi-hit and multi-layered genetic mechanisms implicated in this and other forms of schizophrenia.

Novel deletion of exon 3 in TYR\xa0gene causing Oculocutaneous albinism 1B in an Indian family along with intellectual disability associated with chromosomal copy number variations

BackgroundOculocutaneous albinism (OCA) is an autosomal recessive disorder characterized by hypo-pigmentation of skin, hair, and eyes. The OCA clinical presentation is due to a deficiency of melanin biosynthesis. Intellectual disability (ID) in OCA cases is a rare clinical presentation and appropriate diagnosis of ID is challenging through clinical examination. We report an Indian family with a rare co-inheritance of OCA1B and ID due to a novel TYR gene variant and chromosomal copy number variations.MethodsWe have done a study on three siblings (2 males and 1 female) of a family where all of them presented with hypopigmented skin, hair and eyes. The male children and their father was affected with ID. Targeted exome sequencing and multiplex ligation-dependent probe amplification analysis were carried out to identify the OCA1B and ID associated genomic changes. Further Array-CGH was performed using SurePrint G3 Human CGH + SNP, 8*60 K array.ResultsA rare homozygous deletion of exon 3 in TYR gene causing OCA1B was identified in all three children. The parents were found to be heterozygous carriers. The Array-CGH analysis revealed paternally inherited heterozygous deletion (1.9 MB) of 15q11.1-> 15q11.2 region in all three children. Additionally, paternally inherited heterozygous deletion (2.6 MB) of 10q23.2-> 10q23.31 region was identified in the first male child; this may be associated with ID as the father and the child both presented with ID. While the 2nd male child had a denovo duplication of 13q31.1-> 13q31.3 chromosomal region.ConclusionA rare homozygous TYR gene exon 3 deletion in the present study is the cause of OCA1B in all three children, and the additional copy number variations are associated with the ID. The study highlights the importance of combinational genetic approaches for diagnosing two different co-inherited disorders (OCA and ID). Hence, OCA cases with additional clinical presentation need to be studied in-depth for the appropriate management of the disease.

Identification of a Rare Case With Nagashima-Type Palmoplantar Keratoderma and 18q Deletion Syndrome via Exome Sequencing and Low-Coverage Whole-Genome Sequencing.

Nagashima-type palmoplantar keratoderma (NPPK) is characterized by non-progressive, diffuse, and cross-gradient hyperkeratosis caused by mutations in the SERPINB7 gene on chromosome 18q21.33. Chromosome 18q deletion syndrome (18q- syndrome) is a terminal deletion or microdeletion syndrome characterized by intellectual disability and congenital malformations. This paper describes an 18-year-old man with palmoplantar keratoderma and diffuse white matter abnormalities in the brain. Trio-based exome sequencing (ES) revealed a suspected mosaic compound heterozygous mutation for c.796C>T (p.Arg266∗) in exon 8 inherited from the mother and a de novo exons 4–6 deletion of SERPINB7. Additional copy number variant (CNV) analysis of the ES data indicated a heterozygous gross deletion of 18q22.3-q23. The two SERPINB7 gene variants were verified by Sanger sequencing and quantitative real-time polymerase chain reaction (qRT-PCR). Finally, low-coverage whole-genome sequencing (WGS) confirmed the 18q22.3-q23 deletion and additionally detected a mosaic 18q21.33-q22.3 deletion, together explaining NPPK and the neurological phenotypes of the proband. The gross deletion of all exons of SERPINB7 was revealed for the first time. More rarely, c.796C>T (p.Arg266∗) was likely to be mosaic, while the exon deletion was mosaic. In conclusion, the combination of multiple molecular genetic testing methods provides comprehensive informative molecular findings and promotes the diagnosis of complex diseases, as in this case.

The phenotype of 15 cases with rare 8q24.13‐q24.3 deletions–A new syndrome or still an enigma?

Diagnosis of rare copy number variants (CNVs) with scarce literature evidence poses a major challenge for interpretation of the clinical significance of chromosomal microarray analysis (CMA) results, especially in the prenatal setting. Bioinformatic tools can be used to assist in this issue; however, this prediction can be imprecise. Our objective was to describe the phenotype of the rare copy number losses encompassing the 8q24.13-q24.3 locus, and to find common features in terms of genomic coordinates, gene content, and clinical phenotypic characteristics. Appropriate cases were retrieved using local databases of two largest Israeli centers performing CMA analysis. In addition, literature and public databases search was performed. Local database search yielded seven new patients with del (8)(q24.13q24.3) (one of these with an additional copy number variant). Literature and public databases search yielded eight additional patients. The cases showed high phenotypic variability, ranging from asymptomatic adults and fetuses with normal ultrasound to patients with autism/developmental delay (6/11 postnatal cases, 54.5%). No clear association was noted between the specific disease-causing/high-pLI gene content of the described del (8)(q24.13q24.3) to neurodevelopmental disorders, except for a possibly relevant locus encompassing the KCNQ3 gene. We present the challenges in classification of rare variants with limited clinical information. In such cases, genotype-phenotype correlation must be assessed with extra-caution and possibly using additional methods to assist the classification, especially in the prenatal setting.

Screening of targeted panel genes in Brazilian patients with primary ovarian insufficiency

Primary ovarian insufficiency (POI) is a heterogeneous disorder associated with several genes. The majority of cases are still unsolved. Our aim was to identify the molecular diagnosis of a Brazilian cohort with POI. Genetic analysis was performed using a customized panel of targeted massively parallel sequencing (TMPS) and the candidate variants were confirmed by Sanger sequencing. Additional copy number variation (CNV) analysis of TMPS samples was performed by CONTRA. Fifty women with POI (29 primary amenorrhea and 21 secondary amenorrhea) of unknown molecular diagnosis were included in this study, which was conducted in a tertiary referral center of clinical endocrinology. A genetic defect was obtained in 70% women with POI using the customized TMPS panel. Twenty-four pathogenic variants and two CNVs were found in 48% of POI women. Of these variants, 16 genes were identified as BMP8B, CPEB1, INSL3, MCM9, GDF9, UBR2, ATM, STAG3, BMP15, BMPR2, DAZL, PRDM1, FSHR, EIF4ENIF1, NOBOX, and GATA4. Moreover, a microdeletion and microduplication in the CPEB1 and SYCE1 genes, respectively, were also identified in two distinct patients. The genetic analysis of eleven patients was classified as variants of uncertain clinical significance whereas this group of patients harbored at least two variants in different genes. Thirteen patients had benign or no rare variants, and therefore the genetic etiology remained unclear. In conclusion, next-generation sequencing (NGS) is a highly effective approach to identify the genetic diagnoses of heterogenous disorders, such as POI. A molecular etiology allowed us to improve the disease knowledge, guide decisions about prevention or treatment, and allow familial counseling avoiding future comorbidities.

Development and Analytical Validation of a 29 Gene Clinical Pharmacogenetic Genotyping Panel: Multi‐Ethnic Allele and Copy Number Variant Detection

To develop a novel pharmacogenetic genotyping panel, a multidisciplinary team evaluated available evidence and selected 29 genes implicated in interindividual drug response variability, including 130 sequence variants and additional copy number variants (CNVs). Of the 29 genes, 11 had guidelines published by the Clinical Pharmacogenetics Implementation Consortium. Targeted genotyping and CNV interrogation were accomplished by multiplex single‐base extension using the MassARRAY platform (Agena Biosciences) and multiplex ligation‐dependent probe amplification (MRC Holland), respectively. Analytical validation of the panel was accomplished by a strategic combination of > 500 independent tests performed on 170 unique reference material DNA samples, which included sequence variant and CNV accuracy, reproducibility, and specimen (blood, saliva, and buccal swab) controls. Among the accuracy controls were 32 samples from the 1000 Genomes Project that were selected based on their enrichment of sequence variants included in the pharmacogenetic panel (VarCover.org). Coupled with publicly available samples from the Genetic Testing Reference Materials Coordination Program (GeT‐RM), accuracy validation material was available for the majority (77%) of interrogated sequence variants (100% with average allele frequencies > 0.1%), as well as additional structural alleles with unique copy number signatures (e.g., CYP2D6*5, *13, *36, *68; CYP2B6*29; and CYP2C19*36). Accuracy and reproducibility for both genotyping and copy number were > 99.9%, indicating that the optimized panel platforms were precise and robust. Importantly, multi‐ethnic allele frequencies of the interrogated variants indicate that the vast majority of the general population carries at least one of these clinically relevant pharmacogenetic variants, supporting the implementation of this panel for pharmacogenetic research and/or clinical implementation programs.

High frequency of pathogenic ACAN variants including an intragenic deletion in selected individuals with short stature.

ContextDefining the underlying etiology of idiopathic short stature (ISS) improves the overall management of an individual.ObjectiveTo assess the frequency of pathogenic ACAN variants in selected individuals.DesignThe single-center cohort study was conducted at a tertiary university children’s hospital. From 51 unrelated patients with ISS, the 16 probands aged between 3 and 18 years (12 females) with advanced bone age and/or autosomal dominant inheritance pattern of short stature were selected for the study. Fifteen family members of ACAN-positive probands were included. Exome sequencing was performed in all probands, and additional copy number variation (CNV) detection was applied in selected probands with a distinct ACAN-associated phenotype.ResultsSystematic phenotyping of the study cohort yielded 37.5% (6/16) ACAN-positive probands, with all novel pathogenic variants, including a 6.082 kb large intragenic deletion, detected by array comparative genomic hybridization (array CGH) and exome data analysis. All variants were co-segregated with short stature phenotype, except in one family member with the intragenic deletion who had an unexpected growth pattern within the normal range (−0.5 SDS). One patient presented with otosclerosis, a sign not previously associated with aggrecanopathy.ConclusionsACAN pathogenic variants presented a common cause of familial ISS. The selection criteria used in our study were suggested for a personalized approach to genetic testing of the ACAN gene in clinical practice. Our results expanded the number of pathogenic ACAN variants, including the first intragenic deletion, and suggested CNV evaluation in patients with typical clinical features of aggrecanopathy as reasonable. Intra-familial phenotypic variability in growth patterns should be considered.

Next-Generation Optical Mapping Reveals Numerous Previously Unrecognizable Structural Variants in Chronic Lymphocytic Leukemia

Introduction: Chronic lymphocytic leukemia (CLL) is the most common form of leukemia in adults in western countries. Although a number of genetic aberrations (complex karyotype, del(17p), del(11q), unmutated IGVH status, TP53 mutations) having predictive and prognostic significance in CLL was reported, there is still a lack of information about large structural variants, repetitive regions, copy number variations, and inversions in the CLL genome due to limitations of current methods (NGS, cytogenetics). Aim: Using novel next-generation optical mapping technology, we analyzed leukemic cells from peripheral blood of CLL patients at different stages of the disease. Methods and Patients: High-molecular weight DNA was isolated from peripheral blood (>90% CD5+/CD19+/CD20+/CD23+ B-cells) from two CLL patients (P1: 70-y-old male, diagnosis of CLL in 2018, Binet Stage B, unmutated IGVH, untreated; P2: 59-y-old male, diagnosis of CLL in 2005, Binet Stage A, unmutated IGVH, on ibrutinib (2nd line) since 4/2018). For optical mapping, DNA was labeled by DLS chemistry and visualized on Saphyr system (BioNano Genomics). The optical genome maps (480 Gbp, coverage 124X) were aligned to a human reference genome (GRCh38) and the detected structural variants (SVs) were compared against the database of healthy controls; only rare de novo variants were analyzed. In both patients, cytogenetic analysis (karyotype, FISH, and arrayCGH) and mutational analysis by NGS (TP53, ATM, BIRC3, NOTCH1, SF3B1, POT1 genes) were available. Results: For both CLL patients, the optical mapping method identified 97% of chromosomal abnormalities previously reported by standard cytogenetic methods such as deletions on 6q, 13q, 11q, 17p and trisomy 12. In both patients, same large deletions of 17.5 kbp in 9q21 and 7.1 kbp in 14q21 chromosome region were detected, undetectable by standard methods. Both patients also carried intra-chromosomal translocation t(13;13) located in 13q14 region. Additionally, P1 genome carried 2 kbp deletion in oncogene EGFR and 500 bp insertion affecting tumor suppressor TCF4, both genes previously associated with CLL. Moreover, numerous additional copy number variations and large somatic SVs, including on average tens of deletions, insertions, inversions, duplications, and translocations were detected in both patients. Conclusion: Our study revealed numerous novel genomic rearrangements in CLL genome, unrecognizable by standard methods. These data highlights a high potential of optical maps for refinement of genomic variability in CLL, mainly for detection of large structural variations and copy number variants. The study on larger patient cohort and longer follow-up of patients may identify genetic aberrations associated with the clinical course and therapy response. Support: MZ ČR VES16-32339A, MZ ČR - RVO (FNOl, 00098892), IGA UP_2019_014, IGA UP_2019_01 Disclosures Minarik: Celgene: Consultancy, Honoraria, Research Funding; Amgen, BMS, Janssen-Cilag, Takeda: Consultancy, Honoraria.

Abstract 3602: Validation and implementation of next-generation sequencing in liquid biopsies by a novel NGS platform: Focus on non-small cell lung cancer

Abstract Introduction: Liquid biopsy as a novel and non-invasive test for the surveillance of cancer is rapidly growing, by next-generation sequencing (NGS) technologies with multi-gene panels. Objective: The aim of this study was to describe the validation and implementation of a cell free tumor DNA (cfDNA) from the patients with non-small cell lung cancer (NSCLC), to sequence for 19 genes and copy number variation analyses for 5 genes via a novel NGS platform; GeneReader NGS System. Materials and Methods: We performed the complete NGS workflow with modifications, and sequenced the cfDNA extracted from 100 NSCLC patients. The multi-gene panel includes 19 lung cancer related genes (AKT1, ALK, BRAF, DDR, ERBB2, ESR1, KIT, KRAS, MAP2K1, NRAS, NTRK, PDGFRA, PIK3CA, PTEN and ROS) to sequence and additional copy number variations of 5 genes (RICTOR, EGFR, MET, FGFR1 and ERBB2) that all were selected to represent the most actionable genes for the clinical oncology and molecular diagnostics. The sequencing was performed using a novel NGS platform (GeneReader NGS System, Qiagen). Results: The validation process and the implementation of genetic testing from the cfDNA by this novel NGS system have been utilized for the clinical use. After quality assessment, the data from this NGS system was bioinformatically processed and a tertiary analysis was performed using QCI-Analyze and QCI-Interpret bioinformatics tools. The data was then reviewed on alterations and those reported in different mutation databases. The clinically relevant alterations were identified and reported due to the testing indications. Overall, actionable variants in EGFR, ALK, KRAS, PIK3CA, MET, FGFR1 and ERBB2 genes were detected and reported in 62 % of all NSCLC patients while the majority were in EGFR. Conclusions: For each of the 100 samples tested thus far, at least one variant was detected showing the high sensitivity and specificity of both the multi-gene panel and this novel NGS platform. Our evaluation yielded good results for the actionable multi-gene panel selected and provides a comprehensive NGS analysis and workflow for this new platform. Citation Format: Atil Bisgin, Ozge Sonmezler, Ibrahim Boga. Validation and implementation of next-generation sequencing in liquid biopsies by a novel NGS platform: Focus on non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3602.

Deletion Extents Are Not the Cause of Clinical Variability in 22q11.2 Deletion Syndrome: Does the Interaction between DGCR8 and miRNA-CNVs Play a Major Role?

In humans, the most common genomic disorder is the hemizygous deletion of the chromosome 22q11.2 region, that results in the “22q11.2 deletion syndrome” (22q11.2DS). A peculiarity of 22q11.2DS is its great phenotypic variability that makes this pathology a classic example of a syndrome with variable expressivity and incomplete penetrance. The reasons for this variability have not been elucidated yet, and the molecular substrates underlying the different clinical features of 22q11.2DS are still debated. A cohort of 21 patients has been analyzed by array CGH in order to detect some of the genetic differences that may influence this variability. Two aspects have been investigated: (1) the precise localization of the deletion breakpoints within the low copy repeats (LCRs), (2) the additional Copy Number Variations (CNVs) elsewhere in the genome, by analyzing their gene content. Both protein-coding genes and miRNAs were considered, in order to discover possible epistatic interactions between genes of the 22q11.2 region and the rest of the genome. Eighteen out of twenty-one patients had a deletion of ~3 Mb mediated by LCR22-A and D, whereas 3/21 had a smaller deletion. The breakpoints within the LCR22-A and D do not have a major role in the phenotypic variability since they are rather clustered and the small differences concern genes that are not directly related to clinical signs of 22q11.2DS. A detailed analysis of the gene content of 22q11.2 deleted region indicates that this syndrome could be a bioenergetic disorder or consequence of an altered post-transcriptional gene regulation, due to the presence of DGCR8, a major player of the microRNA (miRNA) biogenesis. Only four genes with mitochondrial function are harbored in the additional CNVs, whereas 11 miRNA, all related to biological pathways present in the 22q11.2DS, have been detected in 19/21 patients. CNVs and miRNAs are new entities that have changed the order of complexity at the level of gene expression and regulation, thus CNV-miRNAs (miRNA harbored in the CNVs) are potential functional variants that should be considered high priority candidate variants in genotype-phenotype association studies. Deletion of DGCR8, the main actor in miRNA biogenesis, amplifies this variability. To our knowledge, this is the first report that focus on the miRNA-CNVs in 22q11.2DS, with the aim of trying to better understand their role in the variable expressivity and incomplete penetrance.

Variable developmental delays and characteristic facial features-A novel 7p22.3p22.2 microdeletion syndrome?

Isolated 7p22.3p22.2 deletions are rarely described with only two reports in the literature. Most other reported cases either involve a much larger region of the 7p arm or have an additional copy number variation. Here, we report five patients with overlapping microdeletions at 7p22.3p22.2. The patients presented with variable developmental delays, exhibiting relative weaknesses in expressive language skills and relative strengths in gross, and fine motor skills. The most consistent facial features seen in these patients included a broad nasal root, a prominent forehead a prominent glabella and arched eyebrows. Additional variable features amongst the patients included microcephaly, metopic ridging or craniosynostosis, cleft palate, cardiac defects, and mild hypotonia. Although the patients' deletions varied in size, there was a 0.47 Mb region of overlap which contained 7 OMIM genes: EIP3B, CHST12, LFNG, BRAT1, TTYH3, AMZ1, and GNA12. We propose that monosomy of this region represents a novel microdeletion syndrome. We recommend that individuals with 7p22.3p22.2 deletions should receive a developmental assessment and a thorough cardiac exam, with consideration of an echocardiogram, as part of their initial evaluation.

Detection of a novel maternally inherited deletion on the x chromosome through single nucleotide polymorphism (SNP) microarray testing on products of conception in a patient with recurrent losses and previously normal karyotype

Chromosomal microarray has demonstrated significant advantages compared to traditional karyotyping through cytogenetic analysis. Not only does it circumvent issues with cell culture and contamination, but it also can identify additional copy number variations at the sub-molecular level (<10 Mb) not recognized by traditional karyotyping. When applied to testing products of conception the use of microarray detected additional copy number variations in 4.4% of samples that were identified as having normal karyotypes through traditional methods.

Distal 22q11.2 Microduplication: Case Report and Review of the Literature.

Distal chromosome 22q11.2 microduplications are associated with a wide range of phenotypes and unclear pathogenicity. The authors report on a 3-year-old girl with global developmental delay harboring a de novo 1.24 Mb distal chromosome 22q11.2 microduplication and a paternally inherited 0.25 Mb chromosome 4p14 microduplication. The authors review clinical features of 30 reported cases of distal 22q11.2 duplications. Common features include developmental delay (93%), neuropsychiatric features (26%), and nonspecific facial dysmorphisms (74%). In 70% of cases, the distal 22q11.2 duplications were inherited, and the majority of the carrier parents were phenotypically normal. Furthermore, 30% of probands carried an additional copy number variant. Review of the phenotype in individuals carrying microduplications involving similar low copy repeats (LCR) failed to establish any clear genotype–phenotype correlations. Distal 22q11.2 duplications represent a major challenge for genetic counseling and prediction of clinical consequences. Our report suggests a pathogenic role of distal 22q11.2 duplications and supports a “multiple hit” hypothesis underlying its variable expressivity and phenotypic severity.

Interstitial deletion of 3p22.3p22.2 encompassing ARPP21 and CLASP2 is a potential pathogenic factor for a syndromic form of intellectual disability: A co‐morbidity model with additional copy number variations in a large family

We describe a family in which four individuals (the mother and three children) presented with an overlapping phenotype of minor physical anomalies and intellectual disability. Four previously unreported copy number variants were found inherited either from the affected mother or from the healthy father, consisting of a 3p22.3p22.2 deletion (2.5 Mb), a 3p24.3 deletion (0.55 Mb), a 6q22.31 duplication (0.74 Mb), all maternally inherited, and an 18q11.2 duplication (0.276 Mb) which was paternally inherited. The deletions on chromosome 3 were both found to segregate with the disease. However, being the 0.55 Mb deleted segment on 3p24.3 devoid of genes, we considered that the 2.5 Mb deletion on 3p22.3p22.2 acts as major pathogenic rearrangement in this condition. Among the transcribed genes residing in this interval, ARPP21 and CLASP2 are proposed as good candidate genes on the basis of their functional properties. A co-morbidity role for the other small rearrangements detected in the affected individuals in association with the 3p22.3p22.2 deletion is also suggested, according to a second-side model of pathogenesis.