A case of mosaic deletion of paternally-inherited PLAGL1 and two cases of upd(6)mat add to evidence for PLAGL1 under-expression as a cause of growth restriction.

PLAGL1 is one of a group of imprinted genes, whose altered expression causes imprinting disorders impacting growth, development, metabolism, and behavior. PLAGL1 over-expression causes transient neonatal diabetes mellitus (TNDM type 1) and, based on murine models, under-expression would be expected to cause growth restriction. However, only some reported individuals with upd(6)mat have growth restriction, giving rise to uncertainty about the role of PLAGL1 in human growth. Here we report three individuals investigated for growth restriction, two with upd(6)mat and one with a mosaic deletion of the paternally-inherited allele of PLAGL1. These cases add to evidence of its involvement in pre- and early post-natal human growth.

Identifying phenotypic expansions for congenital diaphragmatic hernia plus (CDH+) using DECIPHER data.

Congenital diaphragmatic hernia (CDH) can occur in isolation or in conjunction with other birth defects (CDH+). A molecular etiology can only be identified in a subset of CDH cases. This is due, in part, to an incomplete understanding of the genes that contribute to diaphragm development. Here, we used clinical and molecular data from 36 individuals with CDH+ who are cataloged in the DECIPHER database to identify genes that may play a role in diaphragm development and to discover new phenotypic expansions. Among this group, we identified individuals who carried putatively deleterious sequence or copy number variants affecting CREBBP, SMARCA4, UBA2, and USP9X. The role of these genes in diaphragm development was supported by their expression in the developing mouse diaphragm, their similarity to known CDH genes using data from a previously published and validated machine learning algorithm, and/or the presence of CDH in other individuals with their associated genetic disorders. Our results demonstrate how data from DECIPHER, and other public databases, can be used to identify new phenotypic expansions and suggest that CREBBP, SMARCA4, UBA2, and USP9X play a role in diaphragm development.

Optimising Exome Prenatal Sequencing Services (EXPRESS): a study protocol to evaluate rapid prenatal exome sequencing in the NHS Genomic Medicine Service.

Background: Prenatal exome sequencing (ES) for the diagnosis of fetal anomalies was implemented nationally in England in October 2020 by the NHS Genomic Medicine Service (GMS). is the GMS is based around seven regional Genomic Laboratory Hubs (GLHs). Prenatal ES has the potential to significantly improve NHS prenatal diagnostic services by increasing genetic diagnoses and informing prenatal decision-making. Prenatal ES has not previously been offered routinely in a national healthcare system and there are gaps in knowledge and guidance. Methods: Our mixed-methods evaluation commenced in October 2020, aligning with the start date of the NHS prenatal ES service . Study design draws on a framework developed in previous studies of major system innovation. There are five interrelated workstreams. Workstream-1 will use interviews and surveys with professionals, non-participant observations and documentary analysis to produce in-depth case studies across all GLHs. Data collection at multiple time points will track changes over time. In Workstream-2 qualitative interviews with parents offered prenatal ES will explore experiences and establish information and support needs. Workstream-3 will analyse data from all prenatal ES tests for nine-months to establish service outcomes (e.g. diagnostic yield, referral rates, referral sources). Comparisons between GLHs will identify factors (individual or service-related) associated with any variation in outcomes. Workstream-4 will identify and analyse practical ethical problems. Requirements for an effective ethics framework for an optimal and equitable service will be determined. Workstream-5 will assess costs and cost-effectiveness of prenatal ES versus standard tests and evaluate costs of implementing an optimal prenatal ES care pathway. Integration of findings will determine key features of an optimal care pathway from a service delivery, parent and professional perspective. Discussion: The proposed formative and summative evaluation will inform the evolving prenatal ES service to ensure equity of access, high standards of care and benefits for parents across England.

BACKGROUND: Prenatal exome sequencing is a new test that is offered through the NHS Genomic Medicine Service. Prenatal exome sequencing is offered to pregnant women when ultrasound scans suggest that their baby may have a genetic condition that cannot be diagnosed using standard tests. If a genetic condition is diagnosed this can give parents important information about the outlook for their baby. It can also help with their decisions about whether to continue or end the pregnancy, pregnancy management, post-birth care and future pregnancies. STUDY METHODS: The aim of this study is to evaluate the prenatal exome sequencing service. To do this we will; 1. Study how prenatal exome sequencing is delivered across England using surveys and interviews with professionals.2. Interview parents to ask what they think of prenatal exome sequencing and how support and information could be improved3. Look at how many parents have prenatal exome sequencing and the test results. We will look carefully at who has access to the test and whether any particular groups are less likely to be offered testing.4. Conduct workshops with health professionals and parents to identify any practical or ethical problems that arise when prenatal exome sequencing is offered.5. Look at the cost of prenatal exome sequencing and compare it to the cost of other tests that are offered to diagnose genetic conditions in pregnancy.6. Gather our findings together to make recommendations for best practice. Patient and Public Involvement: A patient and public Involvement, engagement and participation (PPIEP) advisory group will work closely with the research team to design the study and develop study materials. They will also help us understand our findings to make sure the information and recommendations that come out of our research will be helpful to parents and the NHS.

The Diagnostic Yield of Prenatal Genetic Technologies in Congenital Heart Disease: A Prospective Cohort Study.

INTRODUCTION: The objective was to evaluate: (i) the proportion of prenatally diagnosed congenital heart disease (CHD) associated with an abnormal quantitative fluorescence-PCR (QF-PCR), chromosome microarray (CMA), and exome sequencing (ES) result; and (ii) the diagnostic yield of these technologies based on CHD category and presence of extra-cardiac anomalies (ECAs). METHODS: This prospective cohort study was set across 12 UK foetal medicine centres. All cases underwent QF-PCR, CMA, and ES, and the diagnostic yield in n = 147 cases of prenatally diagnosed CHD was assessed. RESULTS: In 34.7% (n = 51/147), a genetic diagnosis was obtained. Using a stepwise testing strategy, the diagnostic yield for QF-PCR, CMA, and ES was 15.6% (n = 23/147), 13.7% (n = 17/124), and 10.2% (n = 11/107), respectively. Abnormal QF-PCR/shunt (septal) defects 31.4% (n = 11/35), p = 0.046, and abnormal CMA/conotruncal anomalies 22.7% (n = 10/44), p = 0.04, had significant associations. Monogenic variants were commonest in complex CHD 36.4% (n = 4/11). Multisystem CHD had a greater diagnostic yield overall compared to isolated OR 2.41 (95% CI, 1.1-5.1), particularly in association with brain and gastrointestinal tract anomalies. The proportion of variants of uncertain significance was 4.7% (n = 5/107) with ES, with none in the CMA group. CONCLUSION: In the era of prenatal ES, there remains an important role for QF-PCR and CMA. Identification of monogenic pathologic variants further allows delineation of prognosis in CHD.

Second-trimester prenatal diagnosis of Nager syndrome with a deletion including SF3B4 detected by chromosomal microarray.

Nager syndrome is a rare, complex malformation syndrome, for which there is limited information on prenatal genetic testing. Clinical diagnosis of Nager syndrome, which can be caused by deletions encompassing SF3B4 gene, is possible prenatally. Prenatal chromosomal microarray can aid genotype-phenotype correlation in pregnancies with structural abnormalities seen on ultrasound.

Exome Sequencing for Prenatal Detection of Genetic Abnormalities in Fetal Ultrasound Anomalies: An Economic Evaluation.

INTRODUCTION: In light of the prospective Prenatal Assessment of Genomes and Exomes (PAGE) study, this paper aimed to determine the additional costs of using exome sequencing (ES) alongside or in place of chromosomal microarray (CMA) in a fetus with an identified congenital anomaly. METHODS: A decision tree was populated using data from a prospective cohort of women undergoing invasive diagnostic testing. Four testing strategies were evaluated: CMA, ES, CMA followed by ES ("stepwise"); CMA and ES combined. RESULTS: When ES is priced at GBP 2,100 (EUR 2,407/USD 2,694), performing ES alone prenatally would cost a further GBP 31,410 (EUR 36,001/USD 40,289) per additional genetic diagnosis, whereas the stepwise would cost a further GBP 24,657 (EUR 28,261/USD 31,627) per additional genetic diagnosis. When ES is priced at GBP 966 (EUR 1,107/USD 1,239), performing ES alone prenatally would cost a further GBP 11,532 (EUR 13,217/USD 14,792) per additional genetic diagnosis, whereas the stepwise would cost a further additional GBP 11,639 (EUR 13,340/USD 14,929) per additional genetic diagnosis. The sub-group analysis suggests that performing stepwise on cases indicative of multiple anomalies at ultrasound scan (USS) compared to cases indicative of a single anomaly, is more cost-effective compared to using ES alone. DISCUSSION/CONCLUSION: Performing ES alongside CMA is more cost-effective than ES alone, which can potentially lead to improvements in pregnancy management. The direct effects of test results on pregnancy outcomes were not examined; therefore, further research is recommended to examine changes on the projected incremental cost-effectiveness ratios.

Prenatal chromosomal microarray testing of fetuses with ultrasound structural anomalies: A prospective cohort study of over 1000 consecutive cases.

OBJECTIVE: Evaluate the diagnostic yield of prenatal submicroscopic chromosome anomalies using prenatal array comparative genomic hybridisation (aCGH). METHOD: Prospective cohort study conducted between March 2013 and June 2017 including fetuses where an elevated nuchal translucency (NT) or structural anomaly was identified on ultrasound and common aneuploidy testing was negative. aCGH was performed using an 8-plex oligonucleotide platform with a genome wide backbone resolution of greater than 200 kb and interpretation in line with American College of Medical Genetics guidance. RESULTS: One thousand one hundred twenty-nine fetuses were included; 371 fetuses with an increased NT (32.9%) and 758 with a structural anomaly (67.1%). The rate of pathogenic copy number variants (CNVs) and variant of uncertain significance (VUS) was 5.9% (n = 22) and 0.5% (n = 2) in the elevated NT group and 7.3% (n = 55) and 0.8% (n = 6) in the mid-trimester anomaly group. No pathogenic CNVs were identified in fetuses with an NT less than 4.0 mm. Multisystem and cardiac anomalies had the greatest yield of pathogenic CNV with a 22q11.2 microdeletion present in 40% (12/30). CONCLUSION: Prenatal aCGH is a useful diagnostic tool in the investigation of fetuses with a significantly elevated NT or structural anomaly. With time and experience, rates of pathogenic CNVs have increased, and VUS have reduced, supporting the prenatal application of increasingly high resolution aCGH platforms.

Structural Aberrations with Secondary Implications (SASIs): consensus recommendations for reporting of cancer susceptibility genes identified during analysis of Copy Number Variants (CNVs).

Clinical testing with chromosomal microarray (CMA) is most commonly undertaken for clinical indications such as intellectual disability, dysmorphic features and/or congenital abnormalities. Identification of a structural aberration (SA) involving a cancer susceptibility gene (CSG) constitutes a type of incidental or secondary finding. Laboratory reporting, risk communication and clinical management of these structural aberrations with secondary implications (SASIs) is currently inconsistent. We undertake meta-analysis of 18 622 instances of CMA performed for unrelated indications in which 106 SASIs are identified involving in total 40 different CSGs. Here we present the recommendations of a joint UK working group representing the British Society of Genomic Medicine, UK Cancer Genetics Group and UK Association for Clinical Genomic Science. SASIs are categorised into four groups, defined by the type of SA and the cancer risk. For each group, recommendations are provided regarding reflex parental testing and cancer risk management.

Prenatal exome sequencing analysis in fetal structural anomalies detected by ultrasonography (PAGE): a cohort study.

BACKGROUND: Fetal structural anomalies, which are detected by ultrasonography, have a range of genetic causes, including chromosomal aneuploidy, copy number variations (CNVs; which are detectable by chromosomal microarrays), and pathogenic sequence variants in developmental genes. Testing for aneuploidy and CNVs is routine during the investigation of fetal structural anomalies, but there is little information on the clinical usefulness of genome-wide next-generation sequencing in the prenatal setting. We therefore aimed to evaluate the proportion of fetuses with structural abnormalities that had identifiable variants in genes associated with developmental disorders when assessed with whole-exome sequencing (WES). METHODS: In this prospective cohort study, two groups in Birmingham and London recruited patients from 34 fetal medicine units in England and Scotland. We used whole-exome sequencing (WES) to evaluate the presence of genetic variants in developmental disorder genes (diagnostic genetic variants) in a cohort of fetuses with structural anomalies and samples from their parents, after exclusion of aneuploidy and large CNVs. Women were eligible for inclusion if they were undergoing invasive testing for identified nuchal translucency or structural anomalies in their fetus, as detected by ultrasound after 11 weeks of gestation. The partners of these women also had to consent to participate. Sequencing results were interpreted with a targeted virtual gene panel for developmental disorders that comprised 1628 genes. Genetic results related to fetal structural anomaly phenotypes were then validated and reported postnatally. The primary endpoint, which was assessed in all fetuses, was the detection of diagnostic genetic variants considered to have caused the fetal developmental anomaly. FINDINGS: The cohort was recruited between Oct 22, 2014, and June 29, 2017, and clinical data were collected until March 31, 2018. After exclusion of fetuses with aneuploidy and CNVs, 610 fetuses with structural anomalies and 1202 matched parental samples (analysed as 596 fetus-parental trios, including two sets of twins, and 14 fetus-parent dyads) were analysed by WES. After bioinformatic filtering and prioritisation according to allele frequency and effect on protein and inheritance pattern, 321 genetic variants (representing 255 potential diagnoses) were selected as potentially pathogenic genetic variants (diagnostic genetic variants), and these variants were reviewed by a multidisciplinary clinical review panel. A diagnostic genetic variant was identified in 52 (8·5%; 95% CI 6·4-11·0) of 610 fetuses assessed and an additional 24 (3·9%) fetuses had a variant of uncertain significance that had potential clinical usefulness. Detection of diagnostic genetic variants enabled us to distinguish between syndromic and non-syndromic fetal anomalies (eg, congenital heart disease only vs a syndrome with congenital heart disease and learning disability). Diagnostic genetic variants were present in 22 (15·4%) of 143 fetuses with multisystem anomalies (ie, more than one fetal structural anomaly), nine (11·1%) of 81 fetuses with cardiac anomalies, and ten (15·4%) of 65 fetuses with skeletal anomalies; these phenotypes were most commonly associated with diagnostic variants. However, diagnostic genetic variants were least common in fetuses with isolated increased nuchal translucency (≥4·0 mm) in the first trimester (in three [3·2%] of 93 fetuses). INTERPRETATION: WES facilitates genetic diagnosis of fetal structural anomalies, which enables more accurate predictions of fetal prognosis and risk of recurrence in future pregnancies. However, the overall detection of diagnostic genetic variants in a prospectively ascertained cohort with a broad range of fetal structural anomalies is lower than that suggested by previous smaller-scale studies of fewer phenotypes. WES improved the identification of genetic disorders in fetuses with structural abnormalities; however, before clinical implementation, careful consideration should be given to case selection to maximise clinical usefulness. FUNDING: UK Department of Health and Social Care and The Wellcome Trust.

New GJA8 variants and phenotypes highlight its critical role in a broad spectrum of eye anomalies.

GJA8 encodes connexin 50 (Cx50), a transmembrane protein involved in the formation of lens gap junctions. GJA8 mutations have been linked to early onset cataracts in humans and animal models. In mice, missense mutations and homozygous Gja8 deletions lead to smaller lenses and microphthalmia in addition to cataract, suggesting that Gja8 may play a role in both lens development and ocular growth. Following screening of GJA8 in a cohort of 426 individuals with severe congenital eye anomalies, primarily anophthalmia, microphthalmia and coloboma, we identified four known [p.(Thr39Arg), p.(Trp45Leu), p.(Asp51Asn), and p.(Gly94Arg)] and two novel [p.(Phe70Leu) and p.(Val97Gly)] likely pathogenic variants in seven families. Five of these co-segregated with cataracts and microphthalmia, whereas the variant p.(Gly94Arg) was identified in an individual with congenital aphakia, sclerocornea, microphthalmia and coloboma. Four missense variants of unknown or unlikely clinical significance were also identified. Furthermore, the screening of GJA8 structural variants in a subgroup of 188 individuals identified heterozygous 1q21 microdeletions in five families with coloboma and other ocular and/or extraocular findings. However, the exact genotype-phenotype correlation of these structural variants remains to be established. Our data expand the spectrum of GJA8 variants and associated phenotypes, confirming the importance of this gene in early eye development.

Molecular autopsy by trio exome sequencing (ES) and postmortem examination in fetuses and neonates with prenatally identified structural anomalies.

PURPOSE: To determine the diagnostic yield of combined exome sequencing (ES) and autopsy in fetuses/neonates with prenatally identified structural anomalies resulting in termination of pregnancy, intrauterine, neonatal, or early infant death. METHODS: ES was undertaken in 27 proband/parent trios following full autopsy. Candidate pathogenic variants were classified by a multidisciplinary clinical review panel using American College of Medical Genetics and Genomics (ACMG) guidelines. RESULTS: A genetic diagnosis was established in ten cases (37%). Pathogenic/likely pathogenic variants were identified in nine different genes including four de novo autosomal dominant, three homozygous autosomal recessive, two compound heterozygous autosomal recessive, and one X-linked. KMT2D variants (associated with Kabuki syndrome postnatally) occurred in two cases. Pathogenic variants were identified in 5/13 (38%) cases with multisystem anomalies, in 2/4 (50%) cases with fetal akinesia deformation sequence, and in 1/4 (25%) cases each with cardiac and brain anomalies and hydrops fetalis. No pathogenic variants were detected in fetuses with genitourinary (1), skeletal (1), or abdominal (1) abnormalities. CONCLUSION: This cohort demonstrates the clinical utility of molecular autopsy with ES to identify an underlying genetic cause in structurally abnormal fetuses/neonates. These molecular findings provided parents with an explanation of the developmental abnormality, delineated the recurrence risks, and assisted the management of subsequent pregnancies.

CNVs affecting cancer predisposing genes (CPGs) detected as incidental findings in routine germline diagnostic chromosomal microarray (CMA) testing.

BACKGROUND: Identification of CNVs through chromosomal microarray (CMA) testing is the first-line investigation in individuals with learning difficulties/congenital abnormalities. Although recognised that CMA testing may identify CNVs encompassing a cancer predisposition gene (CPG), limited information is available on the frequency and nature of such results. METHODS: We investigated CNV gains and losses affecting 39 CPGs in 3366 pilot index case individuals undergoing CMA testing, and then studied an extended cohort (n=10 454) for CNV losses at 105 CPGs and CNV gains at 9 proto-oncogenes implicated in inherited cancer susceptibility. RESULTS: In the pilot cohort, 31/3366 (0.92%) individuals had a CNV involving one or more of 16/39 CPGs. 30/31 CNVs involved a tumour suppressor gene (TSG), and 1/30 a proto-oncogene (gain of MET). BMPR1A, TSC2 and TMEM127 were affected in multiple cases. In the second stage analysis, 49/10 454 (0.47%) individuals in the extended cohort had 50 CNVs involving 24/105 CPGs. 43/50 CNVs involved a TSG and 7/50 a proto-oncogene (4 gains, 3 deletions). The most frequently involved genes, FLCN (n=10) and SDHA (n=7), map to the Smith-Magenis and cri-du-chat regions, respectively. CONCLUSION: Incidental identification of a CNV involving a CPG is not rare and poses challenges for future cancer risk estimation. Prospective data collection from CPG-CNV cohorts ascertained incidentally and through syndromic presentations is required to determine the risks posed by specific CNVs. In particular, ascertainment and investigation of adults with CPG-CNVs and adults with learning disability and cancer, could provide important information to guide clinical management and surveillance.

Prenatal whole exome sequencing: the views of clinicians, scientists, genetic counsellors and patient representatives.

OBJECTIVE: Focus groups were conducted with individuals involved in prenatal diagnosis to determine their opinions relating to whole exome sequencing in fetuses with structural anomalies. METHOD: Five representatives of patient groups/charities (PRGs) and eight clinical professionals (CPs) participated. Three focus groups occurred (the two groups separately and then combined). Framework analysis was performed to elicit themes. A thematic coding frame was identified based on emerging themes. RESULTS: Seven main themes (consent, analysis, interpretation/reinterpretation of results, prenatal issues, uncertainty, incidental findings and information access) with subthemes emerged. The main themes were raised by both groups, apart from 'analysis', which was raised by CPs only. Some subthemes were raised by PRGs and CPs (with different perspectives). Others were raised either by PRGs or CPs, showing differences in patient/clinician agendas. CONCLUSIONS: Prenatal consent for whole exome sequencing is not a 'perfect' process, but consent takers should be fully educated regarding the test. PRGs highlighted issues involving access to results, feeling that women want to know all information. PRGs also felt that patients want reinterpretation of results over time, whilst CPs felt that interpretation should be performed at the point of testing only. © 2016 John Wiley & Sons, Ltd.

Genomic complexity of urothelial bladder cancer revealed in urinary cfDNA.

Urothelial bladder cancers (UBCs) have heterogeneous clinical characteristics that are mirrored in their diverse genomic profiles. Genomic profiling of UBCs has the potential to benefit routine clinical practice by providing prognostic utility above and beyond conventional clinicopathological factors, and allowing for prediction and surveillance of treatment responses. Urinary DNAs representative of the tumour genome provide a promising resource as a liquid biopsy for non-invasive genomic profiling of UBCs. We compared the genomic profiles of urinary cellular DNA and cell-free DNA (cfDNA) from the urine with matched diagnostic formalin-fixed paraffin-embedded tumour DNAs for 23 well-characterised UBC patients. Our data show urinary DNAs to be highly representative of patient tumours, allowing for detection of recurrent clinically actionable genomic aberrations. Furthermore, a greater aberrant load (indicative of tumour genome) was observed in cfDNA over cellular DNA (P<0.001), resulting in a higher analytical sensitivity for detection of clinically actionable genomic aberrations (P<0.04) when using cfDNA. Thus, cfDNA extracted from the urine of UBC patients has a higher tumour genome burden and allows greater detection of key genomic biomarkers (90%) than cellular DNA from urine (61%) and provides a promising resource for robust whole-genome tumour profiling of UBC with potential to influence clinical decisions without invasive patient interventions.

Xp11.2 microduplications including IQSEC2, TSPYL2 and KDM5C genes in patients with neurodevelopmental disorders.

Copy number variations are a common cause of intellectual disability (ID). Determining the contribution of copy number variants (CNVs), particularly gains, to disease remains challenging. Here, we report four males with ID with sub-microscopic duplications at Xp11.2 and review the few cases with overlapping duplications reported to date. We established the extent of the duplicated regions in each case encompassing a minimum of three known disease genes TSPYL2, KDM5C and IQSEC2 with one case also duplicating the known disease gene HUWE1. Patients with a duplication encompassing TSPYL2, KDM5C and IQSEC2 without gains of nearby SMC1A and HUWE1 genes have not been reported thus far. All cases presented with ID and significant deficits of speech development. Some patients also manifested behavioral disturbances such as hyperactivity and attention-deficit/hyperactivity disorder. Lymphoblastic cell lines from patients show markedly elevated levels of TSPYL2, KDM5C and SMC1A, transcripts consistent with the extent of their CNVs. The duplicated region in our patients contains several genes known to escape X-inactivation, including KDM5C, IQSEC2 and SMC1A. In silico analysis of expression data in selected gene expression omnibus series indicates that dosage of these genes, especially IQSEC2, is similar in males and females despite the fact they escape from X-inactivation in females. Taken together, the data suggest that gains in Xp11.22 including IQSEC2 cause ID and are associated with hyperactivity and attention-deficit/hyperactivity disorder, and are likely to be dosage-sensitive in males.

Discovery of four recessive developmental disorders using probabilistic genotype and phenotype matching among 4,125 families.

Discovery of most autosomal recessive disease-associated genes has involved analysis of large, often consanguineous multiplex families or small cohorts of unrelated individuals with a well-defined clinical condition. Discovery of new dominant causes of rare, genetically heterogeneous developmental disorders has been revolutionized by exome analysis of large cohorts of phenotypically diverse parent-offspring trios. Here we analyzed 4,125 families with diverse, rare and genetically heterogeneous developmental disorders and identified four new autosomal recessive disorders. These four disorders were identified by integrating Mendelian filtering (selecting probands with rare, biallelic and putatively damaging variants in the same gene) with statistical assessments of (i) the likelihood of sampling the observed genotypes from the general population and (ii) the phenotypic similarity of patients with recessive variants in the same candidate gene. This new paradigm promises to catalyze the discovery of novel recessive disorders, especially those with less consistent or nonspecific clinical presentations and those caused predominantly by compound heterozygous genotypes.

Cross-laboratory validation of the OncoScan® FFPE Assay, a multiplex tool for whole genome tumour profiling.

BACKGROUND: Adoption of new technology in both basic research and clinical settings requires rigorous validation of analytical performance. The OncoScan® FFPE Assay is a multiplexing tool that offers genome-wide copy number and loss of heterozygosity detection, as well as identification of frequently tested somatic mutations. METHODS: In this study, 162 formalin fixed paraffin embedded samples, representing six different tumour types, were profiled in triplicate across three independent laboratories. OncoScan® formalin fixed paraffin embedded assay data was then analysed for reproducibility of genome-wide copy number, loss of heterozygosity and somatic mutations. Where available, somatic mutation data was compared to data from orthogonal technologies (pyro/sanger sequencing). RESULTS: Cross site comparisons of genome-wide copy number and loss of heterozygosity profiles showed greater than 95% average agreement between sites. Somatic mutations pre-validated by orthogonal technologies showed greater than 90% agreement with OncoScan® somatic mutation calls and somatic mutation concordance between sites averaged 97%. CONCLUSIONS: Reproducibility of whole-genome copy number, loss of heterozygosity and somatic mutation data using the OncoScan® assay has been demonstrated with comparatively low DNA inputs from a range of highly degraded formalin fixed paraffin embedded samples. In addition, our data shows examples of clinically-relevant aberrations that demonstrate the potential utility of the OncoScan® assay as a robust clinical tool for guiding tumour therapy.

BAC chromosomal microarray for prenatal detection of chromosome anomalies in fetal ultrasound anomalies: an economic evaluation.

INTRODUCTION: To determine the cost-effectiveness of prenatal chromosomal microarray (CMA) when performed for structural anomalies on fetal ultrasound scan over conventional techniques. METHOD: A decision tree was populated using data from a prospective cohort of women undergoing testing when a fetal ultrasound scan showed a structural abnormality. Nine strategies of testing were modeled including combinations of the tests: QFPCR, G-band karyotyping, CMA and FISH for DiGeorge (22q) microdeletion. RESULTS: When CMA costs GBP 405 and using a 1-Mb BAC array it would cost GBP 24,600 for every additional case detected by CMA over a combination of QFPCR, followed by G-band karyotype, followed lastly by FISH (for DiGeorge syndrome). If CMA is performed instead of conventional karyotyping alone it costs GBP 33,000 for every additional case detected. However, if the cost of CMA is reduced to GBP 360 than when CMA is performed instead of conventional karyotyping alone it would cost GBP 9,768 for every additional case detected. DISCUSSION: The use of a prenatal BAC CMA is not currently cost-effective when compared to other testing strategies. However, as CMA costs decrease and resolution (and detection rates) increase it is likely to become the cost-effective option of the future.

Axenfeld-Rieger syndrome: further clinical and array delineation of four unrelated patients with a 4q25 microdeletion.

Axenfeld-Rieger syndrome (ARS) is an autosomal dominant disorder with variable expressivity. It is characterized by dysgenesis of the anterior segment of the eye together with dental, cardiac, and umbilical anomalies. There is a high incidence of secondary high tension glaucoma. It is a genetically heterogeneous condition due to deletion or mutations of FOXC1 (6p25) or PITX2 (4q25). We report on four unrelated patients with overlapping microdeletions encompassing PITX2 at 4q25. We compare the genotypes and phenotypes of these newly described ARS patients and discuss the involvement of contiguous genes. Patients 1, 2, and 3 had mild learning difficulties, not typically seen in patients with ARS. We implicate the adjacent neuronally expressed genes; NEUROG2, UGT8, NDST3, and PRSS12 as potentially causal. Our findings support the use of microarray analysis in ARS patients for full prognostic information in infants presenting with ARS-like phenotypes.