Prenatal detection of mosaicism for a genome wide uniparental disomy cell line in a cohort of patients: Implications and outcomes.

OBJECTIVES: To investigate the prenatal detection rate of mosaicism by SNP microarray analysis, in which an individual has not one, but two, complete genomes (sets of DNA) in their body, a normal biparental line with a Genome Wide Uniparental Disomy (GWUPD) cell line was used. METHODS: This study retrospectively examines the prenatal detection of GWUPD in a cohort of ∼90,000 prenatal specimens and ∼20,000 products of conceptions (POCs) that were studied by SNP microarray. RESULTS: In total, 25 cases of GWUPD were detected; 16 cases were detected prenatally with GWUPD (∼0.018%) and 9 POCs revealed GWUPD (0.045%). The nine POC specimens presented with placental abnormalities. The 12 amniotic fluid specimens were ascertained because of abnormal ultrasound findings. Nine of 12 pregnancies had findings consistent with Beckwith-Wiedemann syndrome or because of abnormal placentas. However, three pregnancies were detected with GWUPD of maternal origin, with less common findings and demonstrated maternal origin. Four other pregnancies showed GWUPD in a chorionic villus sample, but normal findings in amniotic fluid and apparently normal fetal development. CONCLUSIONS: This cohort with GWUPD mosaicism expands our understanding of GWUPD and has implications for prenatal care and counseling. Additional studies are necessary to understand the rarer maternal GWUPD.

Laboratory performance of genome-wide cfDNA for copy number variants as compared to prenatal microarray.

BACKGROUND: Noninvasive prenatal testing (NIPT) allows for screening of fetal aneuploidy and copy number variants (CNVs) from cell-free DNA (cfDNA) in maternal plasma. Professional societies have not yet embraced NIPT for fetal CNVs, citing a need for additional performance data. A clinically available genome-wide cfDNA test screens for fetal aneuploidy and CNVs larger than 7 megabases (Mb). RESULTS: This study reviews 701 pregnancies with "high risk" indications for fetal aneuploidy which underwent both genome-wide cfDNA and prenatal microarray. For aneuploidies and CNVs considered 'in-scope' for the cfDNA test (CNVs ≥ 7 Mb and select microdeletions), sensitivity and specificity was 93.8% and 97.3% respectively, with positive and negative predictive values of 63.8% and 99.7% as compared to microarray. When including 'out-of-scope' CNVs on array as false negatives, the sensitivity of cfDNA falls to 48.3%. If only pathogenic out-of-scope CNVs are treated as false negatives, the sensitivity is 63.8%. Of the out-of-scope CNVs identified by array smaller than 7 Mb, 50% were classified as variants of uncertain significance (VUS), with an overall VUS rate in the study of 2.29%. CONCLUSIONS: While microarray provides the most robust assessment of fetal CNVs, this study suggests that genome-wide cfDNA can reliably screen for large CNVs in a high-risk cohort. Informed consent and adequate pretest counseling are essential to ensuring patients understand the benefits and limitations of all prenatal testing and screening options.

Uniparental disomy of multiple chromosomes in two cases with a complex phenotype.

Uniparental disomy (UPD) is the inheritance of both chromosomal homologs from one parent. Depending on the chromosome involved and the parental origin, UPD may result in phenotypic abnormalities due to aberrant methylation patterns or unmasking recessive conditions in isodisomic regions. UPD primarily originates from somatic rescue of a single meiotically-derived aneuploidy, most commonly a trisomy. Double UPD is exceedingly rare and triple UPD has not been previously described. Here, we report two unrelated clinical cases with UPD of multiple chromosomes; an 8-month-old male with maternal isodisomy of chromosome 7 and paternal isodisomy of chromosome 9, and a 4-week-old female with mixed paternal UPD for chromosomes 4, 10, and 14. These cases also demonstrate that although extremely rare, the detection of AOH on two or more chromosomes may warrant additional clinical and laboratory investigation such as methylation and STR marker analysis, especially when involving chromosomes known to be associated with imprinting disorders.

Clinical significance and mechanisms associated with segmental UPD.

Whole chromosome uniparental disomy (UPD) has been well documented with mechanisms largely understood. However, the etiology of segmental limited UPD (segUPD) is not as clear. In a 10-year period of confirming (> 300) cases of whole chromosome UPD, we identified 86 segmental cases in both prenatal and postnatal samples. Thirty-two of these cases showed mosaic segmental UPD at 11p due to somatic selection associated with Beckwith-Wiedemann syndrome. This study focuses on apparent mechanisms associated with the remaining cases, many of which appear to represent corrections of genomic imbalance such as deletions and derivative chromosomes. In some cases, segmental UPD was associated with the generation of additional genomic imbalance while in others it apparently resulted in restoration of euploidy. Multiple tests utilizing noninvasive prenatal testing (NIPT), chorionic villus sampling (CVS) and amniotic fluid samples from the same pregnancy revealed temporal evidence of correction and a "hotspot" at 1p. Although in many cases the genomic imbalance was dosage "repaired" in the analyzed tissue, clinical effects could be sustained due to early developmental effects of the original imbalance or due to its continued existence in other tissues. In addition, if correction did not occur in the gametes there would be recurrence risks for the offspring of those individuals. Familial microarray allele patterns are presented that differentiate lack of gamete correction from somatic derived gonadal mosaicism. These results suggest that the incidence of segUPD mediated correction is underestimated and may explain the etiology of some clinical phenotypes which are undetected by routine microarray analysis and many exome sequencing studies.

Hematologists' barriers and enablers to screening and recruiting patients to a chimeric antigen receptor (CAR) T cell therapy trial: a theory-informed interview study.

BACKGROUND: Novel therapies often fail to reach the bedside due to low trial recruitment rates. Prior to conducting one of the first chimeric antigen receptor (CAR) T cell therapy trials in Canada, we used the Theoretical Domains Framework, a novel tool for identifying barriers and enablers to behavior change, to identify physician-related barriers and enablers to screening and recruiting patients for an early phase immunotherapy trial. METHODS: We conducted interviews with hematologists across Canada and used a directed content analysis to identify relevant domains reflecting the key factors that may affect screening and recruitment. RESULTS: In total, we interviewed 15 hematologists. Physicians expressed "cautious hope"; while expressing safety, feasibility, and screening criteria concerns, 14 out of 15 hematologists intended to screen for the trial (domains: knowledge, goals, beliefs about consequences, intentions). Physicians underscored the "challenging contexts," identifying resources, workload, forgetting, and patient wait times to receive CAR T cells as key practical barriers to screening (domains: environmental context and resources, memory, attention and decision-making, behavioral regulation). They also highlighted "variability in roles and procedures" that may lead to missed trial candidates (domain: social and professional role). Left unaddressed, these barriers may undermine trial recruitment. CONCLUSIONS: This study is among the first to use the Theoretical Domains Framework from the physician perspective to identify recruitment challenges to early phase trials and demonstrates the value of this approach for identifying barriers to screening and recruitment that may not otherwise have been elicited. This approach can optimize trial procedures and may serve to inform future promising early phase cancer therapy trials. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03765177 . Registered on December 5, 2018.

Navigating choice in the face of uncertainty: using a theory informed qualitative approach to identifying potential patient barriers and enablers to participating in an early phase chimeric antigen receptor T (CAR-T) cell therapy trial.

OBJECTIVES: Bench to bedside translation of groundbreaking treatments like chimeric antigen receptor T (CAR-T) cell therapy depends on patient participation in early phase trials. Unfortunately, many novel therapies fail to be adequately evaluated due to low recruitment rates, which slows patient access to emerging treatments. Using the Theoretical Domains Framework (TDF), we sought to identify potential patient barriers and enablers to participating in an early phase CAR-T cell therapy trial. DESIGN: We used qualitative semistructured interviews to identify potential barriers and enablers to patients' hypothetical participation in an early phase CAR-T cell therapy trial. We used the TDF and directed content analysis to identify relevant domains based on frequency, relevance and the presence of conflicting beliefs. PARTICIPANTS: Canadian adult patients diagnosed with haematological malignancies. RESULTS: In total, we interviewed 13 participants (8 women, 5 men). Participants ranged in age from 18 to 73 (median=56) and had been living with haematological cancer from a few months to several years. We found participants were unfamiliar with CAR-T cell therapy but wished to know more about treatment safety, efficacy and trial logistics (domains: knowledge, beliefs about consequences). They were motivated by altruistic considerations, though many prioritised personal health benefits despite recognising the goals (ie, establishing safety) of early phase clinical trials (domains: goals, intentions). Every participant valued receiving medical advice from their haematologists and oncologists, though some preferred impartial medical experts to inform their decision making (domain: social influences). Finally, participants indicated that improving access to financial and social supports would improve their trial participation experience (domain: environmental context and resources). CONCLUSION: Using the TDF allowed us to identify factors that might undermine participation to a CAR-T cell therapy trial and to optimise recruitment processes by considering patient perspectives to taking part in early phase trials.Trial regestration: NCT03765177; Pre-results.

Partnering with patients to get better outcomes with chimeric antigen receptor T-cell therapy: towards engagement of patients in early phase trials.

AIM: Though patient engagement in clinical research is growing, recent reports suggest few clinical trials report on such activities. To address this gap, we describe our approach to patient engagement in the development of a clinical trial protocol to assess a new immunotherapy for blood cancer (chimeric antigen receptor T-cell therapy, CAR-T cell therapy). METHODS: Our team developed a clinical trial protocol by working with patient partners from inception. Two patient partners with lived blood cancer experience were identified through referrals from our team's professional network and patient organization contacts. Our patient partners were onboarded to the team and engaged in several studies conducted to develop the clinical trial protocol, including a systematic review of the existing literature on the therapy, patient interviews and a survey to obtain perspectives on barriers and enablers to participating in the trial, an early economic analysis, and a retrospective cohort study. RESULTS: Engaging patient partners enhanced our research in ways that would not have otherwise occurred. By selecting patient important outcomes for data collection, our partners helped flag that quality of life and health utility measures have not been reported in previous CAR-T cell therapy trials for blood cancer. Our partners also co-developed a non-technical summary of the systematic review that summarized results in an accessible manner. Our patient partners reviewed interview and survey questions, to improve the language and appropriateness; provided recruitment suggestions; and provided a patient perspective on the results, thereby confirming the importance of findings. Input was also obtained on costs for the early economic analysis. Our patient partners identified costs that may be a burden to both patients and caregivers during a trial and helped to confirm that the overall structure of the economic model reflected the patient care pathway. Our patient partners also shared their diagnosis and treatment stories, which helped to provide the research team with insight into this experience. CONCLUSIONS: Contributions by our patient partners were invaluable to each component study, as well as the overall development of the trial protocol. We plan to use this approach in the future in order to meaningfully engage patients in the development of other clinical trials; we also hope that by reporting our methods this will help other research teams to do the same. TRIAL REGISTRATION: Affiliated with the development of NCT03765177.

Deletion rescue resulting in segmental homozygosity: A mechanism underlying discordant NIPT results.

With the increasing capabilities of non-invasive prenatal testing (NIPT), detection of sub-chromosomal deletions and duplications are possible. This case series of deletion rescues resulting in segmental homozygosity helps provide a biological explanation for NIPT discrepancies and adds to the dearth of existing literature surrounding segmental UPD cases and their underlying mechanisms. In the three cases presented here, NIPT reported a sub-chromosomal deletion (in isolation or as part of a complex finding). Diagnostic testing, however, revealed segmental homozygosity or UPD for the region reported deleted on NIPT. Postnatal placental testing was pursued in two cases and confirmed the NIPT findings. This discordance between the screening and diagnostic testing is suggestive of a corrective post-zygotic event, such as telomere capture and/or deletion rescue, ultimately resulting in segmental homozygosity and fetoplacental mosaicism. Imprinted chromosomes and autosomal recessive disease genes make homozygosity an important clinical consideration. Amniocentesis with SNP microarray is particularly useful in determining both copy number and UPD issues alike.

Near haploidization is a genomic hallmark which defines a molecular subgroup of giant cell glioblastoma.

BACKGROUND: Giant cell glioblastoma (gcGBM) is a rare histologic subtype of glioblastoma characterized by numerous bizarre multinucleate giant cells and increased reticulin deposition. Compared with conventional isocitrate dehydrogenase (IDH)-wildtype glioblastomas, gcGBMs typically occur in younger patients and are generally associated with an improved prognosis. Although prior studies of gcGBMs have shown enrichment of genetic events, such as TP53 alterations, no defining aberrations have been identified. The aim of this study was to evaluate the genomic profile of gcGBMs to facilitate more accurate diagnosis and prognostication for this entity. METHODS: Through a multi-institutional collaborative effort, we characterized 10 gcGBMs by chromosome studies, single nucleotide polymorphism microarray analysis, and targeted next-generation sequencing. These tumors were subsequently compared to the genomic and epigenomic profile of glioblastomas described in The Cancer Genome Atlas (TCGA) dataset. RESULTS: Our analysis identified a specific pattern of genome-wide massive loss of heterozygosity (LOH) driven by near haploidization in a subset of glioblastomas with giant cell histology. We compared the genomic signature of these tumors against that of all glioblastomas in the TCGA dataset (n = 367) and confirmed that our cohort of gcGBMs demonstrated a significantly different genomic profile. Integrated genomic and histologic review of the TCGA cohort identified 3 additional gcGBMs with a near haploid genomic profile. CONCLUSIONS: Massive LOH driven by haploidization represents a defining molecular hallmark of a subtype of gcGBM. This unusual mechanism of tumorigenesis provides a diagnostic genomic hallmark to evaluate in future cases, may explain reported differences in survival, and suggests new therapeutic vulnerabilities.

Multidisciplinary analysis of pediatric T-ALL: 9q34 gene fusions.

T-cell acute lymphoblastic leukemia (T-ALL) is not as frequently reported as the B-cell counterpart (B-ALL), only occurring in about 15% of pediatric cases with a typically heterogeneous etiology. Approximately 8% of childhood T-ALL cases have rearrangements involving the ABL1 tyrosine kinase gene at 9q34.12; although a t(9;22), resulting in a fusion of ABL1 with the BCR gene at 22q11.23 is a common occurrence in B-ALL, it is not a typical finding in T-ALL. A subset of 10 of 40 documented cases of T-ALL analyzed over a 5-year period is presented, each having gene rearrangements within band 9q34 that resulted in fusions other than BCR/ABL1. These cases included fusions involving ABL1, SET (9q34.11), NUP214 (9q34.13), SPTAN1 (9p34.11), and TNRC6B (22q13.1). Among the 10 cases are: six SET/NUP214 fusions, two ABL1/NUP214 fusions (one of which was associated with episomal amplification) and novel SPTAN1/ABL1 and TNRC6B/ABL1 fusions. The evaluations of these clones were each significantly aided by FISH analysis, which directed subsequent microarray and anchored multiplex PCR testing for fusion confirmations.

Features of Feingold syndrome 1 dominate in subjects with 2p deletions including MYCN.

Interstitial deletions of the distal short arm of chromosome 2 including MYCN have only been reported for a small number of individuals. Germline deletions and mutations of MYCN cause Feingold syndrome 1 (FS1), a rare disorder characterized by microcephaly, digit anomalies, gastrointestinal atresias, short stature, dysmorphic features, and intellectual disability. We present a series of six individuals referred for SNP microarray with overlapping deletions of 2p ranging from 3.4 to 16.8 Mb in size, with a common overlapping region of 1.53 Mb spanning (14,614,477-16,148,021) [hg19] and including five genes: NBAS, DDX1, MYCNUT, MYCNOS, and MYCN. Clinical information was available for five individuals. Clinical features included core features of FS1 such as microcephaly, digit anomalies, and gastrointestinal atresias as well as structural cardiac defects, hearing loss, and renal anomalies, which are features less consistently associated with FS1. Other features observed in several individuals, that have not specifically been associated with FS1 were motor delay, structural brain abnormalities, genital abnormalities, and radioulnar synostosis. These results indicate that while individuals with deletions of 2p spanning several megabases and including MYCN can present with features not typically associated with FS1, the common core features are usually present.

Yield of additional genetic testing after chromosomal microarray for diagnosis of neurodevelopmental disability and congenital anomalies: a clinical practice resource of the American College of Medical Genetics and Genomics (ACMG).

PURPOSE: Chromosomal microarray (CMA) is recommended as the first-tier test in evaluation of individuals with neurodevelopmental disability and congenital anomalies. CMA may not detect balanced cytogenomic abnormalities or uniparental disomy (UPD), and deletion/duplications and regions of homozygosity may require additional testing to clarify the mechanism and inform accurate counseling. We conducted an evidence review to synthesize data regarding the benefit of additional testing after CMA to inform a genetic diagnosis. METHODS: The review was guided by key questions related to the detection of genomic events that may require additional testing. A PubMed search for original research articles, systematic reviews, and meta-analyses was evaluated from articles published between 1 January 1983 and 31 March 2017. Based on the key questions, articles were retrieved and data extracted in parallel with comparison of results and discussion to resolve discrepancies. Variables assessed included study design and outcomes. RESULTS: A narrative synthesis was created for each question to describe the occurrence of, and clinical significance of, additional diagnostic findings from subsequent testing performed after CMA. CONCLUSION: These findings may be used to assist the laboratory and clinician when making recommendations about additional testing after CMA, as it impacts clinical care, counseling, and diagnosis.

Automating Recession Curve Displacement Recharge Estimation.

Recharge estimation is an important and challenging element of groundwater management and resource sustainability. Many recharge estimation methods have been developed with varying data requirements, applicable to different spatial and temporal scales. The variability and inherent uncertainty in recharge estimation motivates the recommended use of multiple methods to estimate and bound regional recharge estimates. Despite the inherent limitations of using daily gauged streamflow, recession curve displacement methods provide a convenient first-order estimate as part of a multimethod hierarchical approach to estimate watershed-scale annual recharge. The implementation of recession curve displacement recharge estimation in the United States Geologic Survey (USGS) RORA program relies on the subjective, operator-specific selection of baseflow recession events to estimate a gauge-specific recession index. This paper presents a parametric algorithm that objectively automates this tedious, subjective process, parameterizing and automating the implementation of recession curve displacement. Results using the algorithm reproduce regional estimates of groundwater recharge from the USGS Appalachian Valley and Piedmont Regional Aquifer-System Analysis, with an average absolute error of less than 2%. The algorithm facilitates consistent, completely automated estimation of annual recharge that complements more rigorous data-intensive techniques for recharge estimation.

Commentary on the decision of the American Board of Medical Genetics and Genomics to create a 24-month specialty of Laboratory Genetics and Genomics.

Genet Med 19 3, 294-296.

Preparation of Amniocytes for Interphase Fluorescence In Situ Hybridization (FISH).

FISH has been used to detect and clarify deletions and/or other structural rearrangements, and also has applications in interphase analysis. This unit describes preparation of uncultured amniotic fluid cells for FISH analysis. Cells are swollen, and then slides are prepared by standard methods. The cells are then fixed and permeabilized for subsequent FISH. An alternate protocol describes attachment of amniocytes to a glass or plastic surface followed by hypotonic swelling, fixation, and permeabilization for subsequent FISH. Interphase FISH analysis of amniotic fluid cells is also described.

Four-copy number intervals in SNP microarray analysis: unique patterns and positions.

Over the past several years, the utility of microarray technology in delineating copy number changes has become well established. In the past 4 years, we have used the SNP array to detect and analyze allele ratios in 150 cases with 4-copy intervals, confirmed by FISH, offering insight into the underlying mechanisms of formation. These cases may be divided into 5 allele patterns--the first 4 of which involve a single homologue--as detected by the genotyping aspects of the microarray: (1) triplications combining homozygous and heterozygous alleles, with a 3:1 ratio of heterozygotes; (2) triplications with allele patterns combining homozygous and heterozygous alleles, with heterozygote ratios of both 3:1 and 2:2; (3) triplications that have homozygous alleles combined with only 2:2 heterozygous alleles; (4) triplications that are completely homozygous; and (5) homozygous duplications on each homologue with no heterozygous alleles. The implications of copy number variants with diverse allelic segregations are presented in this study.

Reciprocal deletion and duplication at 2q23.1 indicates a role for MBD5 in autism spectrum disorder.

Copy number variations associated with abnormal gene dosage have an important role in the genetic etiology of many neurodevelopmental disorders, including intellectual disability (ID) and autism. We hypothesize that the chromosome 2q23.1 region encompassing MBD5 is a dosage-dependent region, wherein deletion or duplication results in altered gene dosage. We previously established the 2q23.1 microdeletion syndrome and report herein 23 individuals with 2q23.1 duplications, thus establishing a complementary duplication syndrome. The observed phenotype includes ID, language impairments, infantile hypotonia and gross motor delay, behavioral problems, autistic features, dysmorphic facial features (pinnae anomalies, arched eyebrows, prominent nose, small chin, thin upper lip), and minor digital anomalies (fifth finger clinodactyly and large broad first toe). The microduplication size varies among all cases and ranges from 68 kb to 53.7 Mb, encompassing a region that includes MBD5, an important factor in methylation patterning and epigenetic regulation. We previously reported that haploinsufficiency of MBD5 is the primary causal factor in 2q23.1 microdeletion syndrome and that mutations in MBD5 are associated with autism. In this study, we demonstrate that MBD5 is the only gene in common among all duplication cases and that overexpression of MBD5 is likely responsible for the core clinical features present in 2q23.1 microduplication syndrome. Phenotypic analyses suggest that 2q23.1 duplication results in a slightly less severe phenotype than the reciprocal deletion. The features associated with a deletion, mutation or duplication of MBD5 and the gene expression changes observed support MBD5 as a dosage-sensitive gene critical for normal development.

Clinical comparison of overlapping deletions of 19p13.3.

We present three patients with overlapping interstitial deletions of 19p13.3 identified by high resolution SNP microarray analysis. All three had a similar phenotype characterized by intellectual disability or developmental delay, structural heart abnormalities, large head relative to height and weight or macrocephaly, and minor facial anomalies. Deletion sizes ranged from 792 Kb to 1.0 Mb and included a common region arr [hg19] 19p13.3 (3,814,392-4,136,989), containing eight genes: ZFR2, ATCAY, NMRK2, DAPK3, EEF2, PIAS4, ZBTB7A, MAP2K2, and two non-coding RNA's MIR637 and SNORDU37. The patient phenotypes were compared with three previous single patient reports with similar interstitial 19p13.3 deletions and six additional patients from the DECIPHER and ISCA databases to determine if a common haploinsufficient phenotype for the region can be established.

Three cases of isolated terminal deletion of chromosome 8p without heart defects presenting with a mild phenotype.

Individuals with isolated terminal deletions of 8p have been well described in the literature, however, molecular characterization, particularly by microarray, of the deletion in most instances is lacking. The phenotype of such individuals falls primarily into two categories: those with cardiac defects, and those without. The architecture of 8p has been demonstrated to contain two inversely oriented segmental duplications at 8p23.1, flanking the gene, GATA4. Haploinsufficiency of this gene has been implicated in cardiac defects seen in numerous individuals with terminal 8p deletion. Current microarray technologies allow for the precise elucidation of the size and gene content of the deleted region. We present three individuals with isolated terminal deletion of 8p distal to the segmental duplication telomeric to GATA4. These individuals present with a relatively mild and nonspecific phenotype including mildly dysmorphic features, developmental delay, speech delay, and early behavior issues.

Double-hit mantle cell lymphoma with MYC gene rearrangement or amplification: a report of four cases and review of the literature.

Mature B-cell lymphomas with both BCL2 and MYC translocations are known as "double hit" lymphomas. These lymphomas are aggressive and show high proliferation rate due to the growth advantages provided by MYC and BCL2 translocation and overexpression. Mantle cell lymphoma (MCL) is a neoplasm of mature B-lymphocytes with characteristic t(11;14) and subsequent Cyclin D1 overexpression. Secondary cytogenetic changes are frequent in MCL, but MYC translocation has only been rarely reported. In this study, we report four cases of MCL with MYC translocation or MYC gene amplification detected by conventional cytogenetics, fluorescence in situ hybridization and whole genome single nucleotide polymorphism (SNP) array, and determined the clinicopathologic features. Our study provides further evidence supporting the concept of "double hit" MCL with co-involvement of MYC gene rearrangement and/or amplification and CCND1 gene rearrangement.