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Journal of Medical Genetics Jul 2017Hydranencephaly is a congenital anomaly leading to replacement of the cerebral hemispheres with a fluid-filled cyst. The goals of this work are to describe a novel...
BACKGROUND
Hydranencephaly is a congenital anomaly leading to replacement of the cerebral hemispheres with a fluid-filled cyst. The goals of this work are to describe a novel autosomal-recessive syndrome that includes hydranencephaly (multinucleated neurons, anhydramnios, renal dysplasia, cerebellar hypoplasia and hydranencephaly (MARCH)); to identify its genetic cause(s) and to provide functional insight into pathomechanism.
METHODS
We used homozygosity mapping and exome sequencing to identify recessive mutations in a single family with three affected fetuses. Immunohistochemistry, RT-PCR and imaging in cell lines, and zebrafish models, were used to explore the function of the gene and the effect of the mutation.
RESULTS
We identified a homozygous nonsense mutation in segregating with MARCH. Testing the effect of this allele on patient-derived cells indicated both a reduction of the overall message and the production of a message that likely gives rise to a truncated protein. Suppression or ablation of in zebrafish embryos recapitulated key features of MARCH, most notably renal dysplasia, cerebellar hypoplasia and craniofacial abnormalities. These phenotypes could be rescued by full-length but not truncated human message. Finally, we expressed the truncated form of CEP55 in human cells, where we observed a failure of truncated protein to localise to the midbody, leading to abscission failure and multinucleated daughter cells.
CONCLUSIONS
loss of function mutations likely underlie MARCH, a novel multiple congenital anomaly syndrome. This association expands the involvement of centrosomal proteins in human genetic disorders by highlighting a role in midbody function.
Topics: Abnormalities, Multiple; Animals; Base Sequence; CRISPR-Cas Systems; Cell Cycle Proteins; Female; Fibroblasts; Gene Editing; Humans; Infant; Male; Mitosis; Models, Biological; Mutation; Neurons; Nuclear Proteins; Pedigree; Phenotype; Subcellular Fractions; Syndrome; Zebrafish; Zebrafish Proteins
PubMed: 28264986
DOI: 10.1136/jmedgenet-2016-104296 -
International Journal of Molecular... Mar 2017Radiosensitivity differs in humans and likely among primates. The reasons are not well known. We examined pre-exposure gene expression in baboons ( = 17) who developed...
Radiosensitivity differs in humans and likely among primates. The reasons are not well known. We examined pre-exposure gene expression in baboons ( = 17) who developed haematologic acute radiation syndrome (HARS) without pancytopenia or a more aggravated HARS with pancytopenia after irradiation. We evaluated gene expression in a two stage study design where stage I comprised a whole genome screen for messenger RNAs (mRNA) (microarray) and detection of 667 microRNAs (miRNA) (real-time quantitative polymerase chain reaction (qRT-PCR) platform). Twenty candidate mRNAs and nine miRNAs were selected for validation in stage II (qRT-PCR). None of the mRNA species could be confirmed during the validation step, but six of the nine selected candidate miRNA remained significantly different during validation. In particular, miR-425-5p (receiver operating characteristic = 0.98; = 0.0003) showed nearly complete discrimination between HARS groups with and without pancytopenia. Target gene searches of miR-425-5p identified new potential mRNAs and associated biological processes linked with radiosensitivity. We found that one miRNA species examined in pre-exposure blood samples was associated with HARS characterized by pancytopenia and identified new target mRNAs that might reflect differences in radiosensitivity of irradiated normal tissue.
Topics: Acute Radiation Syndrome; Animals; Disease Models, Animal; Gene Expression; Gene Expression Profiling; Gene Expression Regulation; Humans; MicroRNAs; Pancytopenia; Papio; RNA, Messenger; Radiation Tolerance
PubMed: 28257102
DOI: 10.3390/ijms18030541 -
Gene expression signature for early prediction of late occurring pancytopenia in irradiated baboons.Annals of Hematology May 2017Based on gene expression changes measured in the peripheral blood within the first 2 days after irradiation, we predicted a pancytopenia in a baboon model. Eighteen...
Based on gene expression changes measured in the peripheral blood within the first 2 days after irradiation, we predicted a pancytopenia in a baboon model. Eighteen baboons were irradiated with 2.5 or 5 Gy. According to changes in blood cell counts, the surviving baboons (n = 17) exhibited a hematological acute radiation syndrome (HARS) either with or without a pancytopenia. We used a two stage study design where stage I was a whole genome screen (microarrays) for mRNA combined with a qRT-PCR platform for simultaneous detection of 667 miRNAs using a part of the samples. Candidate mRNAs and miRNAs differentially upregulated or downregulated (>2-fold, p < 0.05) during the first 2 days after irradiation were chosen for validation in stage II using the remaining samples and using throughout more sensitive qRT-PCR. We detected about twice as many upregulated (mean 2128) than downregulated genes (mean 789) in baboons developing an HARS either with or without a pancytopenia. From 51 candidate mRNAs altogether, 11 mRNAs were validated using qRT-PCR. These mRNAs showed only significant differences between HARS groups and H0, but not between HARS groups with and without pancytopenia. Six miRNA species (e.g., miR-574-3p, p = 0.009, ROC = 0.94) revealed significant gene expression differences between HARS groups with and without pancytopenia and are known to sensitize irradiated cells. Hence, in particular, the newly identified miRNA species for prediction of pancytopenia will support the medical management decision making.
Topics: Animals; Blood Cell Count; Computational Biology; Gene Expression Profiling; Gene Expression Regulation; Genomics; Hemibody Irradiation; Male; MicroRNAs; Pancytopenia; Papio; Prognosis; RNA, Messenger; Reproducibility of Results; Severity of Illness Index; Transcriptome; Whole-Body Irradiation
PubMed: 28236054
DOI: 10.1007/s00277-017-2952-7 -
The Journal of Clinical Investigation Mar 2017Steroid-resistant nephrotic syndrome (SRNS) causes 15% of chronic kidney disease cases. A mutation in 1 of over 40 monogenic genes can be detected in approximately 30%...
Steroid-resistant nephrotic syndrome (SRNS) causes 15% of chronic kidney disease cases. A mutation in 1 of over 40 monogenic genes can be detected in approximately 30% of individuals with SRNS whose symptoms manifest before 25 years of age. However, in many patients, the genetic etiology remains unknown. Here, we have performed whole exome sequencing to identify recessive causes of SRNS. In 7 families with SRNS and facultative ichthyosis, adrenal insufficiency, immunodeficiency, and neurological defects, we identified 9 different recessive mutations in SGPL1, which encodes sphingosine-1-phosphate (S1P) lyase. All mutations resulted in reduced or absent SGPL1 protein and/or enzyme activity. Overexpression of cDNA representing SGPL1 mutations resulted in subcellular mislocalization of SGPL1. Furthermore, expression of WT human SGPL1 rescued growth of SGPL1-deficient dpl1Δ yeast strains, whereas expression of disease-associated variants did not. Immunofluorescence revealed SGPL1 expression in mouse podocytes and mesangial cells. Knockdown of Sgpl1 in rat mesangial cells inhibited cell migration, which was partially rescued by VPC23109, an S1P receptor antagonist. In Drosophila, Sply mutants, which lack SGPL1, displayed a phenotype reminiscent of nephrotic syndrome in nephrocytes. WT Sply, but not the disease-associated variants, rescued this phenotype. Together, these results indicate that SGPL1 mutations cause a syndromic form of SRNS.
Topics: Aldehyde-Lyases; Animals; Cell Line; Cell Movement; Drosophila Proteins; Drosophila melanogaster; Female; Humans; Ichthyosis, Lamellar; Male; Mesangial Cells; Mice; Mice, Knockout; Mutation; Nephrotic Syndrome; Protein Transport; Rats
PubMed: 28165339
DOI: 10.1172/JCI89626 -
Nature Jan 2017XRCC1 is a molecular scaffold protein that assembles multi-protein complexes involved in DNA single-strand break repair. Here we show that biallelic mutations in the...
XRCC1 is a molecular scaffold protein that assembles multi-protein complexes involved in DNA single-strand break repair. Here we show that biallelic mutations in the human XRCC1 gene are associated with ocular motor apraxia, axonal neuropathy, and progressive cerebellar ataxia. Cells from a patient with mutations in XRCC1 exhibited not only reduced rates of single-strand break repair but also elevated levels of protein ADP-ribosylation. This latter phenotype is recapitulated in a related syndrome caused by mutations in the XRCC1 partner protein PNKP and implicates hyperactivation of poly(ADP-ribose) polymerase/s as a cause of cerebellar ataxia. Indeed, remarkably, genetic deletion of Parp1 rescued normal cerebellar ADP-ribose levels and reduced the loss of cerebellar neurons and ataxia in Xrcc1-defective mice, identifying a molecular mechanism by which endogenous single-strand breaks trigger neuropathology. Collectively, these data establish the importance of XRCC1 protein complexes for normal neurological function and identify PARP1 as a therapeutic target in DNA strand break repair-defective disease.
Topics: Adenosine Diphosphate Ribose; Alleles; Animals; Apraxias; Ataxia; Axons; Cerebellar Ataxia; Cerebellum; Chromatin; Cogan Syndrome; DNA Breaks, Single-Stranded; DNA Repair; DNA Repair Enzymes; DNA-Binding Proteins; Female; Humans; Interneurons; Male; Mice; Mutation; Pedigree; Phenotype; Phosphotransferases (Alcohol Group Acceptor); Poly (ADP-Ribose) Polymerase-1; X-ray Repair Cross Complementing Protein 1
PubMed: 28002403
DOI: 10.1038/nature20790 -
Clinical Genetics Aug 2017The short-rib polydactyly syndromes (SRPS) are autosomal recessively inherited, genetically heterogeneous skeletal ciliopathies. SRPS phenotypes were historically...
The short-rib polydactyly syndromes (SRPS) are autosomal recessively inherited, genetically heterogeneous skeletal ciliopathies. SRPS phenotypes were historically categorized as types I-IV, with type I first delineated by Saldino and Noonan in 1972. Characteristic findings among all forms of SRP include short horizontal ribs, short limbs and polydactyly. The SRP type I phenotype is characterized by a very small thorax, extreme micromelia, very short, poorly mineralized long bones, and multiple organ system anomalies. To date, the molecular basis of this most severe type of SRP, also known as Saldino-Noonan syndrome, has not been determined. We identified three SRP cases that fit the original phenotypic description of SRP type I. In all three cases, exome sequence analysis revealed compound heterozygosity for mutations in DYNC2H1, which encodes the main component of the retrograde IFT A motor, cytoplasmic dynein 2 heavy chain 1. Thus SRP type I, II, III and asphyxiating thoracic dystrophy (ATD), which also result from DYNC2H1 mutations. Herein we describe the phenotypic features, radiographic findings, and molecular basis of SRP type I.
Topics: Cytoplasmic Dyneins; Ellis-Van Creveld Syndrome; Female; Fetus; Genetic Heterogeneity; Genetic Predisposition to Disease; Humans; Infant, Newborn; Mutation; Phenotype; Pregnancy; Radiography; Short Rib-Polydactyly Syndrome; Exome Sequencing
PubMed: 27925158
DOI: 10.1111/cge.12947 -
PloS One 2016For effective medical management of radiation-exposed persons after a radiological/nuclear event, blood-based screening measures in the first few days that could predict...
For effective medical management of radiation-exposed persons after a radiological/nuclear event, blood-based screening measures in the first few days that could predict hematologic acute radiation syndrome (HARS) are needed. For HARS severity prediction, we used microRNA (miRNA) expression changes measured on days one and two after irradiation in a baboon model. Eighteen baboons underwent different patterns of partial or total body irradiation, corresponding to an equivalent dose of 2.5 or 5 Gy. According to changes in blood cell counts (BCC) the surviving baboons (n = 17) exhibited mild (H1-2, n = 4) or more severe (H2-3, n = 13) HARS. In a two Stage study design we screened 667 miRNAs using a quantitative real-time polymerase chain reaction (qRT-PCR) platform. In Stage II we validated candidates where miRNAs had to show a similar regulation (up- or down-regulated) and a significant 2-fold miRNA expression difference over H0. Seventy-two candidate miRNAs (42 for H1-2 and 30 for H2-3) were forwarded for validation. Forty-two of the H1-2 miRNA candidates from the screening phase entered the validation step and 20 of them showed a statistically significant 2-4 fold up-regulation relative to the unexposed reference (H0). Fifteen of the 30 H2-3 miRNAs were validated in Stage II. All miRNAs appeared 2-3 fold down-regulated over H0 and allowed an almost complete separation of HARS categories; the strongest candidate, miR-342-3p, showed a sustained and 10-fold down-regulation on both days 1 and 2. In summary, our data support the medical decision making of the HARS even within the first two days after exposure where diagnostic tools for early medical decision are required but so far missing. The miRNA species identified and in particular miR-342-3p add to the previously identified mRNAs and complete the portfolio of identified mRNA and miRNA transcripts for HARS prediction and medical management.
Topics: Acute Radiation Syndrome; Animals; Gene Expression Profiling; Male; MicroRNAs; Papio; RNA; RNA, Messenger; Radiation Exposure; Real-Time Polymerase Chain Reaction; Reproducibility of Results; Time Factors
PubMed: 27846229
DOI: 10.1371/journal.pone.0165307 -
Reumatologia 2016The majority of rheumatic diseases belong to the group of autoimmune diseases and are associated with autoantibody production. Their etiology is not fully understood.... (Review)
Review
The majority of rheumatic diseases belong to the group of autoimmune diseases and are associated with autoantibody production. Their etiology is not fully understood. Certain medications and environmental factors may have an influence on the occurrence of rheumatic diseases. Establishing a cause-effect relationship between a certain factor and disease induction is not always simple. It is important to administer the drug continuously or monitor exposure to a given factor in the period preceding the onset of symptoms. The lack of early diagnosed autoimmune disease, or finally the lack of symptoms within a few weeks/months after discontinuation of the drug/cessation of exposure, is also important. The most frequently mentioned rheumatic diseases caused by drugs and environmental factors include systemic lupus erythematosus (SLE), scleroderma, systemic vasculitis, polymyositis, dermatomyositis, and Sjögren's syndrome. The objective of this study is to summarize current knowledge on rheumatic diseases induced by drugs and environmental factors.
PubMed: 27826170
DOI: 10.5114/reum.2016.62470 -
Scientific Reports Sep 2016Short-rib polydactyly syndromes (SRPS) and Asphyxiating thoracic dystrophy (ATD) or Jeune Syndrome are recessively inherited skeletal ciliopathies characterized by...
Short-rib polydactyly syndromes (SRPS) and Asphyxiating thoracic dystrophy (ATD) or Jeune Syndrome are recessively inherited skeletal ciliopathies characterized by profound skeletal abnormalities and are frequently associated with polydactyly and multiorgan system involvement. SRPS are produced by mutations in genes that participate in the formation and function of primary cilia and usually result from disruption of retrograde intraflagellar (IFT) transport of the cilium. Herein we describe a new spectrum of SRPS caused by mutations in the gene IFT81, a key component of the IFT-B complex essential for anterograde transport. In mutant chondrocytes, the mutations led to low levels of IFT81 and mutant cells produced elongated cilia, had altered hedgehog signaling, had increased post-translation modification of tubulin, and showed evidence of destabilization of additional anterograde transport complex components. These findings demonstrate the importance of IFT81 in the skeleton, its role in the anterograde transport complex, and expand the number of loci associated with SRPS.
PubMed: 27666822
DOI: 10.1038/srep34232 -
Reumatologia 2016The majority of rheumatic diseases belong to the group of autoimmune diseases and are associated with autoantibody production. Their etiology is not fully understood.... (Review)
Review
The majority of rheumatic diseases belong to the group of autoimmune diseases and are associated with autoantibody production. Their etiology is not fully understood. Certain medications and environmental factors may have an influence on the occurrence of rheumatic diseases. Establishing a cause-effect relationship between a certain factor and disease induction is not always simple. It is important to administer the drug continuously or monitor exposure to a given factor in the period preceding the onset of symptoms. The lack of previously diagnosed autoimmune disease, or finally the lack of symptoms within a few weeks/months after discontinuation of the drug/cessation of exposure, is also important. The most frequently mentioned rheumatic diseases caused by drugs and environmental factors include systemic lupus erythematosus, scleroderma, systemic vasculitis, polymyositis, dermatomyositis, and Sjögren's syndrome. The objective of this study is to summarize current knowledge on rheumatic diseases induced by drugs and environmental factors.
PubMed: 27504022
DOI: 10.5114/reum.2016.61212