Mutations in Epigenetic Regulation Genes Are a Major Cause of Overgrowth with Intellectual Disability.

To explore the genetic architecture of human overgrowth syndromes and human growth control, we performed experimental and bioinformatic analyses of 710 individuals with overgrowth (height and/or head circumference ≥+2 SD) and intellectual disability (OGID). We identified a causal mutation in 1 of 14 genes in 50% (353/710). This includes HIST1H1E, encoding histone H1.4, which has not been associated with a developmental disorder previously. The pathogenic HIST1H1E mutations are predicted to result in a product that is less effective in neutralizing negatively charged linker DNA because it has a reduced net charge, and in DNA binding and protein-protein interactions because key residues are truncated. Functional network analyses demonstrated that epigenetic regulation is a prominent biological process dysregulated in individuals with OGID. Mutations in six epigenetic regulation genes-NSD1, EZH2, DNMT3A, CHD8, HIST1H1E, and EED-accounted for 44% of individuals (311/710). There was significant overlap between the 14 genes involved in OGID and 611 genes in regions identified in GWASs to be associated with height (p = 6.84 × 10-8), suggesting that a common variation impacting function of genes involved in OGID influences height at a population level. Increased cellular growth is a hallmark of cancer and there was striking overlap between the genes involved in OGID and 260 somatically mutated cancer driver genes (p = 1.75 × 10-14). However, the mutation spectra of genes involved in OGID and cancer differ, suggesting complex genotype-phenotype relationships. These data reveal insights into the genetic control of human growth and demonstrate that exome sequencing in OGID has a high diagnostic yield.

Fluorescence correlation spectroscopy for multiple-site equilibrium binding: a case of doxorubicin-DNA interaction.

Quantitative description of the interaction between doxorubicin (DOX), a broadly used anticancer drug, and DNA is the key to understand the action mechanism and side effects of its clinical use. However, the reported equilibrium constants of DOX-DNA interaction obtained using a range of different analytical methods vary even by several orders of magnitude. Herein, we propose a novel application of a single-molecule technique - fluorescence correlation spectroscopy (FCS) - to probe the interaction between DOX and two types of DNA (pUC19 and calf thymus DNA), taking advantage of intrinsic self-fluorescence of DOX. We provide an analytical formula for autocorrelation analysis to determine the equilibrium constant of DOX-DNA complex-formation, where binding of multiple DOX molecules to a DNA chain is included in the reaction-diffusion model. Our FCS-based method not only quantitatively revealed the values of equilibrium constant, but also implied that the stability of DOX-DNA complex is related to the types of base pair rather than the length or structure of the DNA. This work opens a promising pathway toward quantitative determination of molecular interactions in complex systems such as living cells or organisms at single-molecule level.

Mutations in the PP2A regulatory subunit B family genes PPP2R5B, PPP2R5C and PPP2R5D cause human overgrowth.

Overgrowth syndromes comprise a group of heterogeneous disorders characterised by excessive growth parameters, often in association with intellectual disability. To identify new causes of human overgrowth, we have been undertaking trio-based exome sequencing studies in overgrowth patients and their unaffected parents. Prioritisation of functionally relevant genes with multiple unique de novo mutations revealed four mutations in protein phosphatase 2A (PP2A) regulatory subunit B family genes protein phosphatase 2, regulatory Subunit B', beta (PPP2R5B); protein phosphatase 2, regulatory Subunit B', gamma (PPP2R5C); and protein phosphatase 2, regulatory Subunit B', delta (PPP2R5D). This observation in 3 related genes in 111 individuals with a similar phenotype is greatly in excess of the expected number, as determined from gene-specific de novo mutation rates (P = 1.43 × 10(-10)). Analysis of exome-sequencing data from a follow-up series of overgrowth probands identified a further pathogenic mutation, bringing the total number of affected individuals to 5. Heterozygotes shared similar phenotypic features including increased height, increased head circumference and intellectual disability. The mutations clustered within a region of nine amino acid residues in the aligned protein sequences (P = 1.6 × 10(-5)). We mapped the mutations onto the crystal structure of the PP2A holoenzyme complex to predict their molecular and functional consequences. These studies suggest that the mutations may affect substrate binding, thus perturbing the ability of PP2A to dephosphorylate particular protein substrates. PP2A is a major negative regulator of v-akt murine thymoma viral oncogene homolog 1 (AKT). Thus, our data further expand the list of genes encoding components of the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/AKT signalling cascade that are disrupted in human overgrowth conditions.

Multi-stage genome-wide association study identifies new susceptibility locus for testicular germ cell tumour on chromosome 3q25.

Recent genome-wide association studies (GWAS) and subsequent meta-analyses have identified over 25 SNPs at 18 loci, together accounting for >15% of the genetic susceptibility to testicular germ cell tumour (TGCT). To identify further common SNPs associated with TGCT, here we report a three-stage experiment, involving 4098 cases and 18 972 controls. Stage 1 comprised previously published GWAS analysis of 307 291 SNPs in 986 cases and 4946 controls. In Stage 2, we used previously published customised Illumina iSelect genotyping array (iCOGs) data across 694 SNPs in 1064 cases and 10 082 controls. Here, we report new genotyping of eight SNPs showing some evidence of association in combined analysis of Stage 1 and Stage 2 in an additional 2048 cases of TGCT and 3944 controls (Stage 3). Through fixed-effects meta-analysis across three stages, we identified a novel locus at 3q25.31 (rs1510272) demonstrating association with TGCT [per-allele odds ratio (OR) = 1.16, 95% confidence interval (CI) = 1.06-1.27; P = 1.2 × 10(-9)].

PALB2, which encodes a BRCA2-interacting protein, is a breast cancer susceptibility gene.

PALB2 interacts with BRCA2, and biallelic mutations in PALB2 (also known as FANCN), similar to biallelic BRCA2 mutations, cause Fanconi anemia. We identified monoallelic truncating PALB2 mutations in 10/923 individuals with familial breast cancer compared with 0/1,084 controls (P = 0.0004) and show that such mutations confer a 2.3-fold higher risk of breast cancer (95% confidence interval (c.i.) = 1.4-3.9, P = 0.0025). The results show that PALB2 is a breast cancer susceptibility gene and further demonstrate the close relationship of the Fanconi anemia-DNA repair pathway and breast cancer predisposition.

Hearing preservation in vestibular schwannoma management.

OBJECTIVE: To compare hearing preservation between stereotactic radiotherapy (SRT) and conservative treatment of patients with unilateral vestibular schwannoma. DATA SOURCES: Retrospective case series comparing hearing outcomes of patients with a unilateral vestibular schwannoma managed conservatively or with stereotactic radiotherapy in a tertiary care academic centre. PATIENTS: Tumor database patients with American Academy of Otolaryngology Head and Neck Surgery Class A or B hearing at the onset of study. Stereotactic radiotherapy patients were predominantly those who failed conservative management. INTERVENTIONS: Audiometric pure tone averages and speech discrimination scores as well as patient demographics, tumor location, size and growth were extracted. MAIN OUTCOME MEASURES: Hearing outcome measures were: 1) Hearing Preservation, i.e. no drop from Class A/B to Class C/D hearing, 2) Hearing Survival of Class A/B hearing in months, 3) Audiometric Pure Tone Averages, Difference between post-treatment and pre-treatment, and 4) Speech Discrimination Score Difference (pre-treatment-post treatment). Survival analysis and non-parametric tests were used for hearing outcome measures, with multiple covariates tested. RESULTS: Overall, serviceable hearing preservation among the 123 patients was 51%. The median hearing survival time was 46 months (mean 59 months). The Pure Tone averages and Speech Discrimination score differences were 16 dB and 82% respectively over a median follow-up time of 43 months. No significant difference was found between the conservative and SRT groups in any hearing outcome. Class A patients showed far better hearing survival than Class B patients. CONCLUSIONS: No significant difference was demonstrated as to measures of hearing outcomes between stereotactic radiotherapy and conservative management. Excellent existing hearing appears to be the best predictor of long term hearing survival in the cohort studied.

Truncating mutations in the Fanconi anemia J gene BRIP1 are low-penetrance breast cancer susceptibility alleles.

We identified constitutional truncating mutations of the BRCA1-interacting helicase BRIP1 in 9/1,212 individuals with breast cancer from BRCA1/BRCA2 mutation-negative families but in only 2/2,081 controls (P = 0.0030), and we estimate that BRIP1 mutations confer a relative risk of breast cancer of 2.0 (95% confidence interval = 1.2-3.2, P = 0.012). Biallelic BRIP1 mutations were recently shown to cause Fanconi anemia complementation group J. Thus, inactivating truncating mutations of BRIP1, similar to those in BRCA2, cause Fanconi anemia in biallelic carriers and confer susceptibility to breast cancer in monoallelic carriers.

Gene-gene interactions in breast cancer susceptibility.

There have been few definitive examples of gene-gene interactions in humans. Through mutational analyses in 7325 individuals, we report four interactions (defined as departures from a multiplicative model) between mutations in the breast cancer susceptibility genes ATM and CHEK2 with BRCA1 and BRCA2 (case-only interaction between ATM and BRCA1/BRCA2 combined, P = 5.9 × 10(-4); ATM and BRCA1, P= 0.01; ATM and BRCA2, P= 0.02; CHEK2 and BRCA1/BRCA2 combined, P = 2.1 × 10(-4); CHEK2 and BRCA1, P= 0.01; CHEK2 and BRCA2, P= 0.01). The interactions are such that the resultant risk of breast cancer is lower than the multiplicative product of the constituent risks, and plausibly reflect the functional relationships of the encoded proteins in DNA repair. These findings have important implications for models of disease predisposition and clinical translation.

Mutation and association analysis of GEN1 in breast cancer susceptibility.

GEN1 was recently identified as a key Holliday junction resolvase involved in homologous recombination. Somatic truncating GEN1 mutations have been reported in two breast cancers. Together these data led to the proposition that GEN1 is a breast cancer predisposition gene. In this article we have formally investigated this hypothesis. We performed full-gene mutational analysis of GEN1 in 176 BRCA1/2-negative familial breast cancer samples and 159 controls. We genotyped six SNPs tagging the 30 common variants in the transcribed region of GEN1 in 3,750 breast cancer cases and 4,907 controls. Mutation analysis revealed one truncating variant, c.2515_2519delAAGTT, which was present in 4% of cases and 4% of controls. We identified control individuals homozygous for the deletion, demonstrating that the last 69 amino acids of GEN1 are dispensable for its function. We identified 17 other variants, but their frequency did not significantly differ between cases and controls. Analysis of 3,750 breast cancer cases and 4,907 controls demonstrated no evidence of significant association with breast cancer for six SNPs tagging the 30 common GEN1 variants. These data indicate that although it also plays a key role in double-strand DNA break repair, GEN1 does not make an appreciable contribution to breast cancer susceptibility by acting as a high- or intermediate-penetrance breast cancer predisposition gene like BRCA1, BRCA2, CHEK2, ATM, BRIP1 and PALB2 and that common GEN1 variants do not act as low-penetrance susceptibility alleles analogous to SNPs in FGFR2. Furthermore, our analyses demonstrate the importance of undertaking appropriate genetic investigations, typically full gene screening in cases and controls together with large-scale case-control association analyses, to evaluate the contribution of genes to cancer susceptibility.

Identification of new Wilms tumour predisposition genes: an exome sequencing study.

BACKGROUND: Wilms tumour is the most common childhood renal cancer and is genetically heterogeneous. While several Wilms tumour predisposition genes have been identified, there is strong evidence that further predisposition genes are likely to exist. Our study aim was to identify new predisposition genes for Wilms tumour. METHODS: In this exome sequencing study, we analysed lymphocyte DNA from 890 individuals with Wilms tumour, including 91 affected individuals from 49 familial Wilms tumour pedigrees. We used the protein-truncating variant prioritisation method to prioritise potential disease-associated genes for further assessment. We evaluated new predisposition genes in exome sequencing data that we generated in 334 individuals with 27 other childhood cancers and in exome data from The Cancer Genome Atlas obtained from 7632 individuals with 28 adult cancers. FINDINGS: We identified constitutional cancer-predisposing mutations in 33 individuals with childhood cancer. The three identified genes with the strongest signal in the protein-truncating variant prioritisation analyses were TRIM28, FBXW7, and NYNRIN. 21 of 33 individuals had a mutation in TRIM28; there was a strong parent-of-origin effect, with all ten inherited mutations being maternally transmitted (p=0·00098). We also found a strong association with the rare epithelial subtype of Wilms tumour, with 14 of 16 tumours being epithelial or epithelial predominant. There were no TRIM28 mutations in individuals with other childhood or adult cancers. We identified truncating FBXW7 mutations in four individuals with Wilms tumour and a de-novo non-synonymous FBXW7 mutation in a child with a rhabdoid tumour. Biallelic truncating mutations in NYNRIN were identified in three individuals with Wilms tumour, which is highly unlikely to have occurred by chance (p<0·0001). Finally, we identified two de-novo KDM3B mutations, supporting the role of KDM3B as a childhood cancer predisposition gene. INTERPRETATION: The four new Wilms tumour predisposition genes identified-TRIM28, FBXW7, NYNRIN, and KDM3B-are involved in diverse biological processes and, together with the other 17 known Wilms tumour predisposition genes, account for about 10% of Wilms tumour cases. The overlap between these 21 constitutionally mutated predisposition genes and 20 genes somatically mutated in Wilms tumour is limited, consisting of only four genes. We recommend that all individuals with Wilms tumour should be offered genetic testing and particularly, those with epithelial Wilms tumour should be offered TRIM28 genetic testing. Only a third of the familial Wilms tumour clusters we analysed were attributable to known genes, indicating that further Wilms tumour predisposition factors await discovery. FUNDING: Wellcome Trust.

A Systematic Review and Comprehensive Critical Analysis Examining the Use of Prednisolone for the Treatment of Mild to Moderate Croup.

BACKGROUND: Many randomised control trials and systematic reviews have examined the benefits of glucocorticoids for the treatment of croup in children, but they have reported mainly on dexamethasone as an oral treatment for croup. No systematic reviews have examined prednisolone alone. AIM: To determine in a systematic review of the literature whether a single dose of oral prednisolone is as effective as a single dose of dexamethasone for reducing croup symptoms in children. SEARCH STRATEGY: A detailed search was conducted on the following databases: CINAHL, MEDLINE EBSCO, MEDLINE, OVID, PubMed, The Cochrane Library, ProQuest, EMBASE, JBI, Sum search, and OpenGrey. Study authors were contacted. SELECTION CRITERIA: Randomised Controlled Trials, clinical trials or chart reviews which examined children with croup who were treated with prednisolone alone, or when prednisolone was compared to a dexamethasone treatment and the effectiveness of the intervention was objectively measured using croup scores and re-attendance as primary outcomes. DATA COLLECTION AND ANALYSIS: Following PRISMA guidelines for systematic reviews, relevant studies were identified. Scores were graded agreed by two independent reviewers using QualSyst. MAIN RESULTS: Four studies met the inclusion criteria, but were too heterogeneous to combine in statistical meta-analysis. The result suggests that although prednisolone appears as effective as dexamethasone when first given, it is less so for preventing re-presentation. Trial sample sizes were small, making firm conclusions difficult, however, a second dose of prednisolone the following day may be useful. More research including cost-benefit analysis is needed to examine the efficacy of prednisolone compared to dexamethasone.

The ICR96 exon CNV validation series: a resource for orthogonal assessment of exon CNV calling in NGS data.

Detection of deletions and duplications of whole exons (exon CNVs) is a key requirement of genetic testing. Accurate detection of this variant type has proved very challenging in targeted next-generation sequencing (NGS) data, particularly if only a single exon is involved. Many different NGS exon CNV calling methods have been developed over the last five years. Such methods are usually evaluated using simulated and/or in-house data due to a lack of publicly-available datasets with orthogonally generated results. This hinders tool comparisons, transparency and reproducibility. To provide a community resource for assessment of exon CNV calling methods in targeted NGS data, we here present the ICR96 exon CNV validation series. The dataset includes high-quality sequencing data from a targeted NGS assay (the TruSight Cancer Panel) together with Multiplex Ligation-dependent Probe Amplification (MLPA) results for 96 independent samples. 66 samples contain at least one validated exon CNV and 30 samples have validated negative results for exon CNVs in 26 genes. The dataset includes 46 exon CNVs in BRCA1, BRCA2, TP53, MLH1, MSH2, MSH6, PMS2, EPCAM or PTEN, giving excellent representation of the cancer predisposition genes most frequently tested in clinical practice. Moreover, the validated exon CNVs include 25 single exon CNVs, the most difficult type of exon CNV to detect. The FASTQ files for the ICR96 exon CNV validation series can be accessed through the European-Genome phenome Archive (EGA) under the accession number EGAS00001002428.

Biallelic TRIP13 mutations predispose to Wilms tumor and chromosome missegregation.

Through exome sequencing, we identified six individuals with biallelic loss-of-function mutations in TRIP13. All six developed Wilms tumor. Constitutional mosaic aneuploidies, microcephaly, developmental delay and seizures, which are features of mosaic variegated aneuploidy (MVA) syndrome, were more variably present. Through functional studies, we show that TRIP13-mutant patient cells have no detectable TRIP13 and have substantial impairment of the spindle assembly checkpoint (SAC), leading to a high rate of chromosome missegregation. Accurate segregation, as well as SAC proficiency, is rescued by restoring TRIP13 function. Individuals with biallelic TRIP13 or BUB1B mutations have a high risk of embryonal tumors, and here we show that their cells display severe SAC impairment. MVA due to biallelic CEP57 mutations, or of unknown cause, is not associated with embryonal tumors and cells from these individuals show minimal SAC deficiency. These data provide insights into the complex relationships between aneuploidy and carcinogenesis.

OpEx - a validated, automated pipeline optimised for clinical exome sequence analysis.

We present an easy-to-use, open-source Optimised Exome analysis tool, OpEx (http://icr.ac.uk/opex) that accurately detects small-scale variation, including indels, to clinical standards. We evaluated OpEx performance with an experimentally validated dataset (the ICR142 NGS validation series), a large 1000 exome dataset (the ICR1000 UK exome series), and a clinical proband-parent trio dataset. The performance of OpEx for high-quality base substitutions and short indels in both small and large datasets is excellent, with overall sensitivity of 95%, specificity of 97% and low false detection rate (FDR) of 3%. Depending on the individual performance requirements the OpEx output allows one to optimise the inevitable trade-offs between sensitivity and specificity. For example, in the clinical setting one could permit a higher FDR and lower specificity to maximise sensitivity. In contexts where experimental validation is not possible, minimising the FDR and improving specificity may be a preferable trade-off for slightly lower sensitivity. OpEx is simple to install and use; the whole pipeline is run from a single command. OpEx is therefore well suited to the increasing research and clinical laboratories undertaking exome sequencing, particularly those without in-house dedicated bioinformatics expertise.

The ICR142 NGS validation series: a resource for orthogonal assessment of NGS analysis.

To provide a useful community resource for orthogonal assessment of NGS analysis software, we present the ICR142 NGS validation series. The dataset includes high-quality exome sequence data from 142 samples together with Sanger sequence data at 704 sites; 416 sites with variants and 288 sites at which variants were called by an NGS analysis tool, but no variant is present in the corresponding Sanger sequence. The dataset includes 293 indel variants and 247 negative indel sites, and thus the ICR142 validation dataset is of particular utility in evaluating indel calling performance. The FASTQ files and Sanger sequence results can be accessed in the European Genome-phenome Archive under the accession number EGAS00001001332.

The ICR1000 UK exome series: a resource of gene variation in an outbred population.

To enhance knowledge of gene variation in outbred populations, and to provide a dataset with utility in research and clinical genomics, we performed exome sequencing of 1,000 UK individuals from the general population and applied a high-quality analysis pipeline that includes high sensitivity and specificity for indel detection. Each UK individual has, on average, 21,978 gene variants including 160 rare (0.1%) variants not present in any other individual in the series. These data provide a baseline expectation for gene variation in an outbred population. Summary data of all 295,391 variants we detected are included here and the individual exome sequences are available from the European Genome-phenome Archive as the ICR1000 UK exome series. Furthermore, samples and other phenotype and experimental data for these individuals are obtainable through application to the 1958 Birth Cohort committee.

Mutations in the transcriptional repressor REST predispose to Wilms tumor.

Wilms tumor is the most common childhood renal cancer. To identify mutations that predispose to Wilms tumor, we are conducting exome sequencing studies. Here we describe 11 different inactivating mutations in the REST gene (encoding RE1-silencing transcription factor) in four familial Wilms tumor pedigrees and nine non-familial cases. Notably, no similar mutations were identified in the ICR1000 control series (13/558 versus 0/993; P < 0.0001) or in the ExAC series (13/558 versus 0/61,312; P < 0.0001). We identified a second mutational event in two tumors, suggesting that REST may act as a tumor-suppressor gene in Wilms tumor pathogenesis. REST is a zinc-finger transcription factor that functions in cellular differentiation and embryonic development. Notably, ten of 11 mutations clustered within the portion of REST encoding the DNA-binding domain, and functional analyses showed that these mutations compromise REST transcriptional repression. These data establish REST as a Wilms tumor predisposition gene accounting for ∼2% of Wilms tumor.

Germline mutations in the PAF1 complex gene CTR9 predispose to Wilms tumour.

Wilms tumour is a childhood kidney cancer. Here we identify inactivating CTR9 mutations in 3 of 35 Wilms tumour families, through exome and Sanger sequencing. By contrast, no similar mutations are present in 1,000 population controls (P<0.0001). Each mutation segregates with Wilms tumour in the family and a second mutational event is present in available tumours. CTR9 is a key component of the polymerase-associated factor 1 complex which has multiple roles in RNA polymerase II regulation and is implicated in embryonic organogenesis and maintenance of embryonic stem cell pluripotency. These data establish CTR9 as a Wilms tumour predisposition gene and suggest it acts as a tumour suppressor gene.

Mutations in CEP57 cause mosaic variegated aneuploidy syndrome.

Using exome sequencing and a variant prioritization strategy that focuses on loss-of-function variants, we identified biallelic, loss-of-function CEP57 mutations as a cause of constitutional mosaic aneuploidies. CEP57 is a centrosomal protein and is involved in nucleating and stabilizing microtubules. Our findings indicate that these and/or additional functions of CEP57 are crucial for maintaining correct chromosomal number during cell division.