54 resultados para [omim]
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[Hermann Jacob Rinald]
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We describe an apparently new genetic syndrome in six members of a family living in a remote area in Northeastern Brazil. This syndrome comprises: short stature Clue to a marked decrease in the length of the lower limbs (predominantly mesomelic with fibular agenesis/marked hypoplasia), grossly malformed/deformed clubfeet with severe oligodactyly, tipper limbs with acromial dimples and variable motion limitation of the forearms and/or hands, severe nail hypoplasia/anonychia sometimes associated with mild brachydactyly and occasionally with pre-axial polydactyly. This syndrome is apparently distinct from the syndrome of brachydactyly-ectrodactyly with fibular aplasia or hypoplasia (OMIM 113310), the syndrome of fibular aplasia or hypoplasia, femoral bowing and poly-, syn-, and oligodactyly (OMIM 228930), and from other previously described conditions exhibiting fibular agenesis/hvpoplasia. (C) 2008 Wiley-Liss, Inc.
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Wolcott-Rallison syndrome (WRS, OMIM 226980) is a rare autosomal recessive disorder characterized by permanent neonatal diabetes mellitus, epiphyseal dysplasia, and other multisystemic clinical manifestations. We described two novel mutations in the EIF2AK3 gene in two consanguineous families with WRS from Brazil and Morocco. We have observed in case 1 a homozygous C > T replacement at base pair c.1192 at exon 7, generating a stop codon at position 398 (Gln398Stop). Both of his parents were found to be heterozygous for the mutation. We detected in both parents of case 2, a deceased Moroccan girl, a duplication of base pair c.851A at exon 5 (c.851dupA) leading to a frameshift and a stop codon at position 285 (p.Pro285AlafsX3). Both cases 1 and 2 had neonatal diabetes mellitus, multiple epiphyseal dysplasia, and growth delay, and presented episodes of acute hepatic dysfunction. Case 1 presented central hypothyroidism, developmental delay, and mild mental retardation. Case 2 presented a fatal episode of acute renal failure. The clinical phenotype associated with the syndrome can be variable, but a combination of infancy-onset diabetes mellitus, multiple epiphyseal dysplasia, and hepatic and/or renal dysfunction is the mainstay of diagnosis.
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We report the identification of a novel mutation at a highly conserved residue within the N-terminal region of spermine synthase (SMS) in a second family with Snyder-Robinson X-linked mental retardation syndrome ( OMIM 309583). This missense mutation, p.G56S, greatly reduces SMS activity and leads to severe epilepsy and cognitive impairment. Our findings contribute to a better delineation and expansion of the clinical spectrum of Snyder-Robinson syndrome, support the important role of the N-terminus in the function of the SMS protein, and provide further evidence for the importance of SMS activity in the development of intellectual processing and other aspects of human development.
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Dissertação de Mestrado, Ciências Biomédicas, 5 de Outubro de 2015, Universidade dos Açores.
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Dissertação para obtenção do Grau de Mestre em Biotecnologia
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The objective of the work presented in this thesis was the development of an innovative approach for the separation of enantiomers of secondary alcohols, combining the use of an ionic liquid (IL) - both as solvent for conducting enzymatic kinetic resolution and as acylating agent - with the use of carbon dioxide (CO2) as solvent for extraction. Menthol was selected for testing this reaction/separation approach due to the increasing demand for this substance, which is widely used in the pharmaceutical, cosmetics and food industries. With a view to using an ionic ester as acylating agent, whose conversion led to the release of ethanol, and due to the need to remove this alcohol so as to drive reaction equilibrium forward, a phase equilibrium study was conducted for the ehtanol/(±)-menthol/CO2 system, at pressures between 8 and 10 MPa and temperatures between 40 and 50 oC. It was found that CO2 is more selective towards ethanol, especially at the lowest pressure and highest temperature tested, leading to separation factors in the range 1.6-7.6. The pressure-temperature-composition data obtained were correlated with the Peng-Robinson equation of state and the Mathias-Klotz-Prausnitz mixing rule. The model fit the experimental results well, with an average absolute deviation (AAD) of 3.7 %. The resolution of racemic menthol was studied using two lipases, namely lipase from Candida rugosa (CRL) and immobilized lipase B from Candida antarctica (CALB), and two ionic acylating esters. No reaction was detected in either case. (R,S)-1-phenylethanol was used next, and it was found that with CRL low, nonselective, conversion of the alcohol took place, whereas CALB led to an enantiomeric excess (ee) of the substrate of 95%, at 30% conversion. Other acylating agents were tested for the resolution of (±)-menthol, namely vinyl esters and acid anhydrides, using several lipases and varying other parameters that affect conversion and enantioselectivity, such as substrate concentration, solvent and temperature. One such acylating agent was propionic anhydride. It was thus performed a phase equilibrium study on the propionic anhydride/CO2 system, at temperatures between 35 and 50 oC. This study revealed that, at 35 oC and pressures from 7 MPa, the system is monophasic for all compositions. The enzymatic catalysis studies carried out with propionic anhydride revealed that the extent of noncatalyzed reaction was high, with a negative effect on enantioselectivity. These studies showed also that it was possible to reduce considerably the impact of the noncatalyzed reaction relative to the reaction catalyzed by CRL by lowering temperature to 4 oC. Vinyl decanoate was shown to lead to the best results at conditions amenable to a process combining the use of supercritical CO2 as agent for post-reaction separation. The use of vinyl decanoate in a number of IL solvents, namely [bmim][PF6], [bmim][BF4], [hmim][PF6], [omim][PF6], and [bmim][Tf2N], led to an enantiomeric excess of product (eep) values of over 96%, at about 50% conversion, using CRL. In n-hexane and supercritical CO2, reaction progressed more slowly.(...)
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Williams-Beuren syndrome (WBS; OMIM no. 194050) is a multisystemic neurodevelopmental disorder caused by a hemizygous deletion of 1.55 Mb on chromosome 7q11.23 spanning 28 genes. Haploinsufficiency of the ELN gene was shown to be responsible for supravalvular aortic stenosis and generalized arteriopathy, whereas LIMK1, CLIP2, GTF2IRD1 and GTF2I genes were suggested to be linked to the specific cognitive profile and craniofacial features. These insights for genotype-phenotype correlations came from the molecular and clinical analysis of patients with atypical deletions and mice models. Here we report a patient showing mild WBS physical phenotype and normal IQ, who carries a shorter 1 Mb atypical deletion. This rearrangement does not include the GTF2IRD1 and GTF2I genes and only partially the BAZ1B gene. Our results are consistent with the hypothesis that hemizygosity of the GTF2IRD1 and GTF2I genes might be involved in the facial dysmorphisms and in the specific motor and cognitive deficits observed in WBS patients.
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The Al-Awadi-Raas-Rothschild syndrome (AARRS; OMIM 276820) and the Fuhrmann syndrome (FS; OMIM 228930) are distinct limb malformation disorders comprising different degrees of limb aplasia or hypoplasia. In 2006, Woods et al. found different recessive WNT7A mutations in one family segregating the AARRS phenotype and in a second family with FS. To explain the common genetic basis for the two clinically distinct disorders, functional studies were done showing that partial loss of WNT7A function resulted in FS, while complete loss of WNT7A function resulted in the more severe phenotype of AARRS. In spite of the elucidation of the molecular basis of AARRS, there remains to this day considerable diagnostic confusion that has culminated in the lumping of Schinzel phocomelia syndrome with AARRS; however, this phocomelic limb defect is quite different in its clinical aspect and pathogenesis from the limb findings of AARRS. Here, we report on a child with the AARRS phenotype and homozygosity for a non-conservative E72K mutation in WNT7A, underline the homogeneity of the WNT7A-associated AARRS phenotype, and propose differential diagnostic criteria for the AARRS reflecting the roles of WNT7A in limb development.
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Loss-of-function variants in innate immunity genes are associated with Mendelian disorders in the form of primary immunodeficiencies. Recent resequencing projects report that stop-gains and frameshifts are collectively prevalent in humans and could be responsible for some of the inter-individual variability in innate immune response. Current computational approaches evaluating loss-of-function in genes carrying these variants rely on gene-level characteristics such as evolutionary conservation and functional redundancy across the genome. However, innate immunity genes represent a particular case because they are more likely to be under positive selection and duplicated. To create a ranking of severity that would be applicable to innate immunity genes we evaluated 17,764 stop-gain and 13,915 frameshift variants from the NHLBI Exome Sequencing Project and 1,000 Genomes Project. Sequence-based features such as loss of functional domains, isoform-specific truncation and nonsense-mediated decay were found to correlate with variant allele frequency and validated with gene expression data. We integrated these features in a Bayesian classification scheme and benchmarked its use in predicting pathogenic variants against Online Mendelian Inheritance in Man (OMIM) disease stop-gains and frameshifts. The classification scheme was applied in the assessment of 335 stop-gains and 236 frameshifts affecting 227 interferon-stimulated genes. The sequence-based score ranks variants in innate immunity genes according to their potential to cause disease, and complements existing gene-based pathogenicity scores. Specifically, the sequence-based score improves measurement of functional gene impairment, discriminates across different variants in a given gene and appears particularly useful for analysis of less conserved genes.
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Cousin syndrome, also called pelviscapular dysplasia (OMIM 260660), is characterized by short stature, craniofacial dysmorphism, and multiple skeletal anomalies. Following its description in two sibs in 1982, no new cases have been observed until the observation of two unrelated cases in 2008 who were homozygous for frameshift mutations in TBX15. We investigated an adult individual with short stature, a complex craniofacial dysmorphism, malformed and rotated ears, short neck, elbow contractures, hypoacusis, and hypoplasia of scapula and pelvis on radiographs. We identified homozygosity for a novel nonsense mutation (c.841C>T) in TBX15 predicted to cause a premature stop (p.Arg281*) with truncation of the protein. This observation confirms that Cousin syndrome is a consistent and clinically recognizable phenotype caused by loss of function of TBX15.
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Hirschsprung disease (HSCR, OMIM 142623) is a developmental disorder characterized by the absence of ganglion cells along variable lengths of the distal gastrointestinal tract, which results in tonic contraction of the aganglionic gut segment and functional intestinal obstruction. The RET proto-oncogene is the major gene for HSCR with differential contributions of its rare and common, coding and noncoding mutations to the multifactorial nature of this pathology. Many other genes have been described to be associated with the pathology, as NRG1 gene (8p12), encoding neuregulin 1, which is implicated in the development of the enteric nervous system (ENS), and seems to contribute by both common and rare variants. Here we present the results of a comprehensive analysis of the NRG1 gene in the context of the disease in a series of 207 Spanish HSCR patients, by both mutational screening of its coding sequence and evaluation of 3 common tag SNPs as low penetrance susceptibility factors, finding some potentially damaging variants which we have functionally characterized. All of them were found to be associated with a significant reduction of the normal NRG1 protein levels. The fact that those mutations analyzed alter NRG1 protein would suggest that they would be related with HSCR disease not only in Chinese but also in a Caucasian population, which reinforces the implication of NRG1 gene in this pathology.
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ABSTRACTThe Online Mendelian Inheritance in Man database (OMIM) reports about 3000 Mendelian diseases of known causal gene and about 2000 that remain to be mapped. These cases are often difficult to solve because of the rareness of the disease, the structure of the family (too big or too small) or the heterogeneity of the phenotype. The goal of this thesis is to explore the current genetic tools, before the advent of ultra high throughput sequencing, and integrate them in the attempt to map the genes behind the four studied cases. In this framework we have studied a small family with a recessive disease, a modifier gene for the penetrance of a dominant mutation, a large extended family with a cardiac phenotype and clinical and/or allelic heterogeneity and we have molecularly analyzed a balanced chromosomal translocation.RESUMELa base de données des maladies à transmission mendélienne, Online Mendelian Inheritance in Man (OMIM), contient environ 3000 affections à caractère mendélien pour lesquelles le gène responsable est connu et environ 2000 qui restent à élucider.Les cas restant à résoudre sont souvent difficiles soit par le caractère intrinsèquement rare de ces maladies soit à cause de difficultés structurelles (famille trop petite ou trop étendue) ou hétérogénéité du phénotype ou génétique. Cette thèse s'inscrit avant l'arrivée des nouveaux outils de séquençage à haut débit. Son but est d'explorer les outils génétiques actuels, et de les intégrer pour trouver les gènes impliqués dans quatre cas représentant chacun une situation génétique différente : nous avons étudié une famille de quatre individus avec une transmission récessive, recherché un gène modificateur de la pénétrance de mutations dominantes, étudié une famille étendue présentant un phénotype cardiaque cliniquement et/ou allèliquement hétérogène et nous avons fait l'analyse moléculaire d'une translocation chromosomique balancée.
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Patients with defective ectodysplasin A (EDA) have X-linked hypohidrotic ectodermal dysplasia (XLHED; OMIM#305100), a condition comprising hypotrichosis, inability to sweat, abnormal teeth, and frequent pulmonary infections. The XLHED dogs show the same clinical signs as humans with the disorder, including frequent respiratory infections that can be fatal. The respiratory disease in humans and dogs is thought to be due to the absence of tracheal and bronchial glands which are a vital part of the mucociliary clearance mechanism. In our XLHED model, the genetically missing EDA was replaced by postnatal intravenous administration of recombinant EDA resulting in long-term, durable corrective effect on adult, permanent dentition. After treatment with EDA, significant correction of the missing tracheal and bronchial glands was achieved in those dogs that received higher doses of EDA. Moreover, successful treatment resulted in the presence of esophageal glands, improved mucociliary clearance, and the absence of respiratory infection. These results demonstrate that a short-term treatment at a neonatal age with a recombinant protein can reverse a developmental disease and result in vastly improved quality of life.
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Focal dermal hypoplasia (FDH; Goltz-Gorlin syndrome; OMIM 305600) is a disorder that features involvement of the skin, skeletal system, and eyes. It is caused by loss-of-function mutations in the PORCN gene. We report a young girl with FDH, microphthalmos associated with colobomatous orbital cyst, dural ectasia and cystic malformation of the spinal cord, and a de novo variant in PORCN. This association has not been previously reported, and based on these observations the phenotypic spectrum of FDH might be broader than previously appreciated. It would be prudent to alter the suggested surveillance for this rare disorder. © 2013 Wiley Periodicals, Inc.