A comparative benchmark of classic DNA motif discovery tools on synthetic data.

Hundreds of human proteins were found to establish transient interactions with rather degenerated consensus DNA sequences or motifs. Identifying these motifs and the genomic sites where interactions occur represent one of the most challenging research goals in modern molecular biology and bioinformatics. The last twenty years witnessed an explosion of computational tools designed to perform this task, whose performance has been last compared fifteen years ago. Here, we survey sixteen of them, benchmark their ability to identify known motifs nested in twenty-nine simulated sequence datasets, and finally report their strengths, weaknesses, and complementarity.

MitImpact 3: modeling the residue interaction network of the Respiratory Chain subunits.

Numerous lines of evidence have shown that the interaction between the nuclear and mitochondrial genomes ensures the efficient functioning of the OXPHOS complexes, with substantial implications in bioenergetics, adaptation, and disease. Their interaction is a fascinating and complex trait of the eukaryotic cell that MitImpact explores with its third major release. MitImpact expands its collection of genomic, clinical, and functional annotations of all non-synonymous substitutions of the human mitochondrial genome with new information on putative Compensated Pathogenic Deviations and co-varying amino acid sites of the Respiratory Chain subunits. It further provides evidence of energetic and structural residue compensation by techniques of molecular dynamics simulation. MitImpact is freely accessible at http://mitimpact.css-mendel.it.

MiRLog and dbmiR: Prioritization and functional annotation tools to study human microRNA sequence variants.

The recent identification of noncoding variants with pathogenic effects suggests that these variations could underlie a significant number of undiagnosed cases. Several computational methods have been developed to predict the functional impact of noncoding variants, but they exhibit only partial concordance and are not integrated with functional annotation resources, making the interpretation of these variants still challenging. MicroRNAs (miRNAs) are small noncoding RNA molecules that act as fine regulators of gene expression and play crucial functions in several biological processes, such as cell proliferation and differentiation. An increasing number of studies demonstrate a significant impact of miRNA single nucleotide variants (SNVs) both in Mendelian diseases and complex traits. To predict the functional effect of miRNA SNVs, we implemented a new meta-predictor, MiRLog, and we integrated it into a comprehensive database, dbmiR, which includes a precompiled list of all possible miRNA allelic SNVs, providing their biological annotations at nucleotide and miRNA levels. MiRLog and dbmiR were used to explore the genetic variability of miRNAs in 15,708 human genomes included in the gnomAD project, finding several ultra-rare SNVs with a potentially deleterious effect on miRNA biogenesis and function representing putative contributors to human phenotypes.

Biallelic variant in cyclin B3 is associated with failure of maternal meiosis II and recurrent digynic triploidy.

BACKGROUND: Triploidy is one of the most common chromosome abnormalities affecting human gestation and accounts for an important fraction of first-trimester miscarriages. Triploidy has been demonstrated in a few cases of recurrent pregnancy loss (RPL) but its molecular mechanisms are unknown. This study aims to identify the genetic cause of RPL associated with fetus triploidy. METHODS: We investigated genomic imprinting, genotyped sequence-tagged site (STS) markers and performed exome sequencing in a family including two sisters with RPL. Moreover, we evaluated oocyte maturation in vivo and in vitro and effect of the candidate protein variant in silico. RESULTS: While features of hydatidiform mole were excluded, the presence of triploidy of maternal origin was demonstrated in the fetuses. Oocyte maturation was deficient and all the maternally inherited pericentromeric STS alleles were homozygous in the fetuses. A deleterious missense variant (p.V1251D) of the cyclin B3 gene (CCNB3) affecting a residue conserved in placental mammals and located in a region that can interact with the cyclin-dependent kinase 1 or cyclin-dependent kinase 2 cosegregated in homozygosity with RPL. CONCLUSION: Here, we report a family in which a damaging variant in cyclin B3 is associated with the failure of oocyte meiosis II and recurrent fetus triploidy, implicating a rationale for CCNB3 testing in RPL.

Genomic inversions and GOLGA core duplicons underlie disease instability at the 15q25 locus.

Human chromosome 15q25 is involved in several disease-associated structural rearrangements, including microdeletions and chromosomal markers with inverted duplications. Using comparative fluorescence in situ hybridization, strand-sequencing, single-molecule, real-time sequencing and Bionano optical mapping analyses, we investigated the organization of the 15q25 region in human and nonhuman primates. We found that two independent inversions occurred in this region after the fission event that gave rise to phylogenetic chromosomes XIV and XV in humans and great apes. One of these inversions is still polymorphic in the human population today and may confer differential susceptibility to 15q25 microdeletions and inverted duplications. The inversion breakpoints map within segmental duplications containing core duplicons of the GOLGA gene family and correspond to the site of an ancestral centromere, which became inactivated about 25 million years ago. The inactivation of this centromere likely released segmental duplications from recombination repression typical of centromeric regions. We hypothesize that this increased the frequency of ectopic recombination creating a hotspot of hominid inversions where dispersed GOLGA core elements now predispose this region to recurrent genomic rearrangements associated with disease.

Copy number variation analysis implicates novel pathways in patients with oculo-auriculo-vertebral-spectrum and congenital heart defects.

Oculo-auriculo-vertebral spectrum (OAVS) is a developmental disorder of craniofacial morphogenesis. Its etiology is unclear, but assumed to be complex and heterogeneous, with contribution of both genetic and environmental factors. We assessed the occurrence of copy number variants (CNVs) in a cohort of 19 unrelated OAVS individuals with congenital heart defect. Chromosomal microarray analysis identified pathogenic CNVs in 2/19 (10.5%) individuals, and CNVs classified as variants of uncertain significance in 7/19 (36.9%) individuals. Remarkably, two subjects had small intragenic CNVs involving DACH1 and DACH2, two paralogs coding for key components of the PAX-SIX-EYA-DACH network, a transcriptional regulatory pathway controlling developmental processes relevant to OAVS and causally associated with syndromes characterized by craniofacial involvement. Moreover, a third patient showed a large duplication encompassing DMBX1/OTX3, encoding a transcriptional repressor of OTX2, another transcription factor functionally connected to the DACH-EYA-PAX network. Among the other relevant CNVs, a deletion encompassing HSD17B6, a gene connected with the retinoic acid signaling pathway, whose dysregulation has been implicated in craniofacial malformations, was also identified. Our findings suggest that CNVs affecting gene dosage likely contribute to the genetic heterogeneity of OAVS, and implicate the PAX-SIX-EYA-DACH network as novel pathway involved in the etiology of this developmental trait.

Electrocardiogram in Friedreich's ataxia: A short-term surrogate endpoint for treatment efficacy.

Friedreich's ataxia is a rare degenerative neuromuscular disorder, caused by a homozygous GAA triplet repeat expansion in the frataxin (FXN) gene, with a broad clinical phenotype characterized by progressive gait and limb ataxia, dysarthria, and loss of lower limb reflexes; cardiac involvement is represented by hypertrophic cardiomyopathy, ventricular arrhythmias, and sudden cardiac deaths. Currently, no definite therapy is available, while many drugs are under investigation; for this reasons, we need markers of short- and long-term treatment efficacy acting on different tissue for trial evaluation. We describe the case of a 21-year-old patient affected by Friedreich's ataxia on wheel-chair, with initial cardiac involvement and electrocardiographic features characterized by thiamine treatment-related negative T wave and QTc variations. We discuss plausible physiopathology and potential ECG role implications as an intermediate marker of treatment response in future clinical trials considering patients affected by Friedreich's ataxia.

A Novel Genetic Variant in the WFS1 Gene in a Patient with Partial Uniparental Mero-Isodisomy of Chromosome 4.

Wolfram syndrome is a rare autosomal recessive disorder characterized by optic atrophy and diabetes mellitus. Wolfram syndrome type 1 (WFS1) is caused by bi-allelic pathogenic variations in the wolframin gene. We described the first case of WFS1 due to a maternal inherited mutation with uniparental mero-isodisomy of chromosome 4. Diabetes mellitus was diagnosed at 11 years of age, with negative anti-beta cells antibodies. Blood glucose control was optimal with low insulin requirement. No pathogenic variations in the most frequent gene causative of maturity-onset diabetes of the young subtypes were detected. At 17.8 years old, a rapid reduction in visual acuity occurred. Genetic testing revealed the novel homozygous variant c.1369A>G; p.Arg457Gly in the exon 8 of wolframin gene. It was detected in a heterozygous state only in the mother while the father showed a wild type sequence. In silico disease causing predictions performed by Polyphen2 classified it as "likely damaging", while Mutation Tester and Sift suggested it was "polymorphism" and "tolerated", respectively. High resolution SNP-array analysis was suggestive of segmental uniparental disomy on chromosome 4. In conclusion, to the best of our knowledge, we describe the first patient with partial uniparental mero-isodisomy of chromosome 4 carrying a novel mutation in the wolframin gene. The clinical phenotype observed in the patient and the analysis performed suggest that the genetic variant detected is pathogenetic.

Dissecting molecular mechanisms of resistance to NOTCH1-targeted therapy in T-cell acute lymphoblastic leukemia xenografts.

Despite substantial progress in treatment of T-cell acute lymphoblastic leukemia (T-ALL), mortality remains relatively high, mainly due to primary or acquired resistance to chemotherapy. Further improvements in survival demand better understanding of T-ALL biology and development of new therapeutic strategies. The Notch pathway has been involved in the pathogenesis of this disease and various therapeutic strategies are currently under development, including selective targeting of NOTCH receptors by inhibitory antibodies. We previously demonstrated that the NOTCH1-specific neutralizing antibody OMP52M51 prolongs survival in TALL patient-derived xenografts bearing NOTCH1/FBW7 mutations. However, acquired resistance to OMP52M51 eventually developed and we used patient-derived xenografts models to investigate this phenomenon. Multi-level molecular characterization of T-ALL cells resistant to NOTCH1 blockade and serial transplantation experiments uncovered heterogeneous types of resistance, not previously reported with other Notch inhibitors. In one model, resistance appeared after 156 days of treatment, it was stable and associated with loss of Notch inhibition, reduced mutational load and acquired NOTCH1 mutations potentially affecting the stability of the heterodimerization domain. Conversely, in another model resistance developed after only 43 days of treatment despite persistent down-regulation of Notch signaling and it was accompanied by modulation of lipid metabolism and reduced surface expression of NOTCH1. Our findings shed light on heterogeneous mechanisms adopted by the tumor to evade NOTCH1 blockade and support clinical implementation of antibody-based target therapy for Notch-addicted tumors.

Double missense mutations in cardiac myosin-binding protein C and myopalladin genes: A case report with diffuse coronary disease, complete atrioventricular block, and progression to dilated cardiomyopathy.

Cardiomyopathies caused by double gene mutations are rare but conferred a remarkably increased risk of end-stage progression, arrhythmias, and poor outcome. Compound genetic mutations leading to complex phenotype in the setting of cardiomyopathies represent an important challenge in clinical practice, and genetic tests allow risk stratification and personalized clinical management of patients. We report a case of a 50-year-old woman with congestive heart failure characterized by dilated cardiomyopathy, diffuse coronary disease, complete atrioventricular block, and missense mutations in cardiac myosin-binding protein C (MYBPC3) and myopalladin (MYPN). We discuss the plausible role of genetic profile in phenotype determination.

A Link between Genetic Disorders and Cellular Impairment, Using Human Induced Pluripotent Stem Cells to Reveal the Functional Consequences of Copy Number Variations in the Central Nervous System-A Close Look at Chromosome 15.

Recent cutting-edge human genetics technology has allowed us to identify copy number variations (CNVs) and has provided new insights for understanding causative mechanisms of human diseases. A growing number of studies show that CNVs could be associated with physiological mechanisms linked to evolutionary trigger, as well as to the pathogenesis of various diseases, including cancer, autoimmune disease and mental disorders such as autism spectrum disorders, schizophrenia, intellectual disabilities or attention-deficit/hyperactivity disorder. Their incomplete penetrance and variable expressivity make diagnosis difficult and hinder comprehension of the mechanistic bases of these disorders. Additional elements such as co-presence of other CNVs, genomic background and environmental factors are involved in determining the final phenotype associated with a CNV. Genetically engineered animal models are helpful tools for understanding the behavioral consequences of CNVs. However, the genetic background and the biology of these animal model systems have sometimes led to confusing results. New cellular models obtained through somatic cellular reprogramming technology that produce induced pluripotent stem cells (iPSCs) from human subjects are being used to explore the mechanisms involved in the pathogenic consequences of CNVs. Considering the vast quantity of CNVs found in the human genome, we intend to focus on reviewing the current literature on the use of iPSCs carrying CNVs on chromosome 15, highlighting advantages and limits of this system with respect to mouse model systems.

Sudden death in mild hypertrophic cardiomyopathy with compound DSG2/DSC2/MYH6 mutations: Revisiting phenotype after genetic assessment in a master runner athlete.

Cardiomyopathies represent a well-known cause of heart failure and sudden death. Although cardiomyopathies are generally categorized in distinct nosographic entities, characterized by single gene-to-disease causal relationships, recently, oligogenic mutations have also been associated to relevant cardiac clinical features. We report the case of a master athlete carrying trigenic mutations in desmoglein-2 (DSG2), desmocollin-2 (DSC2) and heavy chain myosin 6 (MYH6), which determine a mild hypertrophic phenotype associated both to ventricular tachyarrhythmias and atrio-ventricular block. We discuss the differential diagnosis and prognostic approach in patient affected by complex cardiomyopathy phenotype, along with the importance of sport restriction and sudden death prevention.

A single-center study on 140 patients with cerebral cavernous malformations: 28 new pathogenic variants and functional characterization of a PDCD10 large deletion.

Cerebral cavernous malformation (CCM) is a capillary malformation arising in the central nervous system. CCM may occur sporadically or cluster in families with autosomal dominant transmission, incomplete penetrance, and variable expressivity. Three genes are associated with CCM KRIT1, CCM2, and PDCD10. This work is a retrospective single-center molecular study on samples from multiple Italian clinical providers. From a pool of 317 CCM index patients, we found germline variants in either of the three genes in 80 (25.2%) probands, for a total of 55 different variants. In available families, extended molecular analysis found segregation in 60 additional subjects, for a total of 140 mutated individuals. From the 55 variants, 39 occurred in KRIT1 (20 novel), 8 in CCM2 (4 novel), and 8 in PDCD10 (4 novel). Effects of the three novel KRIT1 missense variants were characterized in silico. We also investigated a novel PDCD10 deletion spanning exon 4-10, on patient's fibroblasts, which showed significant reduction of interactions between KRIT1 and CCM2 encoded proteins and impaired autophagy process. This is the largest study in Italian CCM patients and expands the known mutational spectrum of KRIT1, CCM2, and PDCD10. Our approach highlights the relevance of seeking supporting information to pathogenicity of new variants for the improvement of management of CCM.

Loss-of-Function Mutations in APPL1 in Familial Diabetes Mellitus.

Diabetes mellitus is a highly heterogeneous disorder encompassing several distinct forms with different clinical manifestations including a wide spectrum of age at onset. Despite many advances, the causal genetic defect remains unknown for many subtypes of the disease, including some of those forms with an apparent Mendelian mode of inheritance. Here we report two loss-of-function mutations (c.1655T>A [p.Leu552(∗)] and c.280G>A [p.Asp94Asn]) in the gene for the Adaptor Protein, Phosphotyrosine Interaction, PH domain, and leucine zipper containing 1 (APPL1) that were identified by means of whole-exome sequencing in two large families with a high prevalence of diabetes not due to mutations in known genes involved in maturity onset diabetes of the young (MODY). APPL1 binds to AKT2, a key molecule in the insulin signaling pathway, thereby enhancing insulin-induced AKT2 activation and downstream signaling leading to insulin action and secretion. Both mutations cause APPL1 loss of function. The p.Leu552(∗) alteration totally abolishes APPL1 protein expression in HepG2 transfected cells and the p.Asp94Asn alteration causes significant reduction in the enhancement of the insulin-stimulated AKT2 and GSK3ß phosphorylation that is observed after wild-type APPL1 transfection. These findings-linking APPL1 mutations to familial forms of diabetes-reaffirm the critical role of APPL1 in glucose homeostasis.

Clinical and molecular characterization of an emerging chromosome 22q13.31 microdeletion syndrome.

Microdeletion of chromosome 22q13.31 is a very rare condition. Fourteen patients have been annotated in public databases but, to date, a clinical comparison has not been done and, consequently, a specific phenotype has not been delineated yet. We describe a patient showing neurodevelopmental disorders, dysmorphic features, and multiple congenital anomalies in which SNP array analysis revealed an interstitial 3.15 Mb de novo microdeletion in the 22q13.31 region encompassing 21 RefSeq genes and seven non-coding microRNAs. To perform an accurate phenotype characterization, clinical features observed in previously reported cases of 22q13.31 microdeletions were reviewed and compared to those observed in our patient. To the best of our knowledge, this is the first time that a comparison between patients carrying overlapping 22q13.31 deletions has been done. This comparison allowed us to identify a distinct spectrum of clinical manifestations suggesting that patients with a de novo interstitial microdeletion involving 22q13.31 have an emerging syndrome characterized by developmental delay/intellectual disability, speech delay/language disorders, behavioral problems, hypotonia, urogenital, and hands/feet anomalies. The microdeletion identified in our patient is the smallest reported so far and, for this reason, useful to perform a detailed genotype-phenotype correlation. In particular, we propose the CELSR1, ATXN10, FBLN1, and UPK3A as candidate genes in the onset of the main clinical features of this contiguous gene syndrome. Thus, the patient reported here broadens our knowledge of the phenotypic consequences of 22q13.31 microdeletions facilitating genotype-phenotype correlations. Additional cases are needed to corroborate our hypothesis and confirm genotype-phenotype correlations of this emerging syndrome.

High-confidence assessment of functional impact of human mitochondrial non-synonymous genome variations by APOGEE.

24,189 are all the possible non-synonymous amino acid changes potentially affecting the human mitochondrial DNA. Only a tiny subset was functionally evaluated with certainty so far, while the pathogenicity of the vast majority was only assessed in-silico by software predictors. Since these tools proved to be rather incongruent, we have designed and implemented APOGEE, a machine-learning algorithm that outperforms all existing prediction methods in estimating the harmfulness of mitochondrial non-synonymous genome variations. We provide a detailed description of the underlying algorithm, of the selected and manually curated training and test sets of variants, as well as of its classification ability.

Multifaceted enrichment analysis of RNA-RNA crosstalk reveals cooperating micro-societies in human colorectal cancer.

Alterations in the balance of mRNA and microRNA (miRNA) expression profiles contribute to the onset and development of colorectal cancer. The regulatory functions of individual miRNA-gene pairs are widely acknowledged, but group effects are largely unexplored. We performed an integrative analysis of mRNA-miRNA and miRNA-miRNA interactions using high-throughput mRNA and miRNA expression profiles obtained from matched specimens of human colorectal cancer tissue and adjacent non-tumorous mucosa. This investigation resulted in a hypernetwork-based model, whose functional backbone was fulfilled by tight micro-societies of miRNAs. These proved to modulate several genes that are known to control a set of significantly enriched cancer-enhancer and cancer-protection biological processes, and that an array of upstream regulatory analyses demonstrated to be dependent on miR-145, a cell cycle and MAPK signaling cascade master regulator. In conclusion, we reveal miRNA-gene clusters and gene families with close functional relationships and highlight the role of miR-145 as potent upstream regulator of a complex RNA-RNA crosstalk, which mechanistically modulates several signaling pathways and regulatory circuits that when deranged are relevant to the changes occurring in colorectal carcinogenesis.

Sudden cardiac death in J wave syndrome with short QT associated to a novel mutation in Nav 1.8 coding gene SCN10A: First case report for a possible pharmacogenomic role.

INTRODUCTION: Sudden cardiac death is an important cause of mortality in the general population. It represents an important challenge for clinicians, often being the only symptom of a broad spectrum of cardiac pathologies and inherited heart conditions. Early repolarization syndrome and Brugada syndrome are part of the wider "J-wave" syndrome, which may also include the short QT syndrome as a third factor of an ionic channel imbalance in the arrhythmogenic landscape. CASE PRESENTATION: We describe the case of a woman struck down by sudden cardiac death, with short QT and early repolarization, in which we found an extremely rare and putatively pathogenic heterozygous variant in the SCN10A gene. Variants involving SCN10A, which encodes a voltage-gated sodium channel, were already associated with alterations of cardiac conduction parameters and the cardiac rhythm disorder, thereby influencing the cardiac physiology and predisposing to arrhythmia. CONCLUSION: We underline the role of genetic predisposition to sudden cardiac death and, for the first time, suggest a possible environmental effect, such as a pharmacological therapy in the setting of sudden death, with the purpose to increase awareness in clinical practice.