Browsing by Author "Barbot, C."
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- Genes, crianças e pediatras: defeito congénito da N-glicosilação tipo IaPublication . Nascimento, P.; Martins, M.; Pereira, A.; Barbot, C.; Martins, E.
- High germinal instability of the (CTG)n at the SCA8 locus of both expanded and normal allelesPublication . Silveira, I.; Afonso, I.; Guimarães, L.; Mendonça, P.; Santos, C.; Maciel, P.; Matos, J.; Costa, M.; Barbot, C.; Tuna, A.; Barros, J.; Jardim, L.; Coutinho, P.; Sequeiros, J.Abstract The autosomal dominant spinocerebellar ataxias (SCAs) are a group of late-onset, neurodegenerative disorders for which 10 loci have been mapped (SCA1, SCA2, SCA4-SCA8, SCA10, MJD, and DRPLA). The mutant proteins have shown an expanded polyglutamine tract in SCA1, SCA2, MJD/SCA3, SCA6, SCA7, and DRPLA; a glycine-to-arginine substitution was found in SCA6 as well. Recently, an untranslated (CTG)n expansion on chromosome 13q was described as being the cause of SCA8. We have now (1) assessed the repeat size in a group of patients with ataxia and a large number of controls, (2) examined the intergenerational transmission of the repeat, and (3) estimated the instability of repeat size in the sperm of one patient and two healthy controls. Normal SCA8 chromosomes showed an apparently trimodal distribution, with classes of small (15-21 CTGs), intermediate (22-37 CTGs), and large (40-91 CTGs) alleles; large alleles accounted for only0.7% of all normal-size alleles. No expanded alleles (>/=100 CTGs) were found in controls. Expansion of the CTG tract was found in five families with ataxia; expanded alleles (all paternally transmitted) were characterized mostly by repeat-size contraction. There was a high germinal instability of both expanded and normal alleles: in one patient, the expanded allele (152 CTGs) had mostly contraction in size (often into the normal range); in the sperm of two normal controls, contractions were also more frequent, but occasional expansions into the upper limit of the normal size range were also seen. In conclusion, our results show (1) no overlapping between control (15-91) and pathogenic (100-152) alleles and (2) a high instability in spermatogenesis (both for expanded and normal alleles), suggesting a high mutational rate at the SCA8 locus.
- Homozygosity mapping of a third Joubert syndrome locus to 6q23.Publication . Lagier-Tourenne, C.; Boltshauser, E.; Breivik, N.; Gribaa, M.; Bétard, C.; Barbot, C.; Koenig, M.J Med Genet. 2004 Apr;41(4):273-7. Homozygosity mapping of a third Joubert syndrome locus to 6q23. Lagier-Tourenne C, Boltshauser E, Breivik N, Gribaa M, Bétard C, Barbot C, Koenig M. IGBMC, CNRS/INSERM/ULP, Illkirch, C.U. de Strasbourg, France. Abstract BACKGROUND: Joubert syndrome (JS) is a recessively inherited disorder characterised by hypotonia at birth and developmental delay, followed by truncal ataxia and cognitive impairment, characteristic neuroimaging findings (cerebellar vermis hypoplasia, "molar tooth sign") and suggestive facial features. JS is clinically heterogeneous with some patients presenting with breathing abnormalities in the neonatal period, oculomotor apraxia, retinal dystrophy, retinal coloboma, ptosis, hexadactyly, and nephronophtisis or cystic dysplastic kidneys. JS is also genetically heterogeneous, with two known loci, on 9q34 (JBTS1) and 11p11-q12 (CORS2), representing only a fraction of cases. METHODS: A large consanguineous Joubert family (five affected) was analysed for linkage with a marker set covering the entire genome and 16 smaller families were subsequently tested for candidate loci. RESULTS: We report here the identification of a third locus in 6q23 (JBTS3) from the study of two consanguineous families. LOD score calculation, including the consanguinity loops, gave a maximum value of 4.1 and 2.3 at q = 0 for the two families, respectively. CONCLUSIONS: Linkage between the disease and the D6S1620-D6S1699 haplotype spanning a 13.1 cM interval is demonstrated. Genotype-phenotype studies indicate that, unlike CORS2, JBTS3 appears not to be associated with renal dysfunction. PMID: 15060101 [PubMed - indexed for MEDLINE]PMCID: PMC1735723
- Homozygosity mapping of Portuguese and Japanese forms of ataxia-oculomotor apraxia to 9p13, and evidence for genetic heterogeneity.Publication . Moreira, M.; Barbot, C.; Tachi, N.; Kozuka, N.; Mendonça, P.; Barros, J.; Coutinho, P.; Sequeiros, J.; Koenig, M.Abstract Ataxia with oculomotor apraxia (AOA) is characterized by early-onset cerebellar ataxia, ocular apraxia, early areflexia, late peripheral neuropathy, slow progression, severe motor handicap, and absence of both telangiectasias and immunodeficiency. We studied 13 Portuguese families with AOA and found that the two largest families show linkage to 9p, with LOD scores of 4.13 and 3.82, respectively, at a recombination fraction of 0. These and three smaller families, all from northern Portugal, showed homozygosity and haplotype sharing over a 2-cM region on 9p13, demonstrating the existence of both a founding event and linkage to this locus, AOA1, in the five families. Three other families were excluded from this locus, demonstrating nonallelic heterogeneity in AOA. Early-onset cerebellar ataxia with hypoalbuminemia (EOCA-HA), so far described only in Japan, is characterized by marked cerebellar atrophy, peripheral neuropathy, mental retardation, and, occasionally, oculomotor apraxia. Two unrelated Japanese families with EOCA-HA were analyzed and appeared to show linkage to the AOA1 locus. Subsequently, hypoalbuminemia was found in all five Portuguese patients with AOA1 with a long disease duration, suggesting that AOA1 and EOCA-HA correspond to the same entity that accounts for a significant proportion of all recessive ataxias. The narrow localization of AOA1 should prompt the identification of the defective gene.
- Homozygosity mapping of Portuguese and Japanese forms of ataxia-oculomotor apraxia to 9p13, and evidence for genetic heterogeneity.Publication . Moreira, M.C.; Barbot, C.; Tachi, N.; Kozuka, N.; Mendonça, P.; Barros, J.; Coutinho, P.; Sequeiros, J.; Koenig, M.Am J Hum Genet. 2001 Feb;68(2):501-8. Epub 2001 Jan 22. Homozygosity mapping of Portuguese and Japanese forms of ataxia-oculomotor apraxia to 9p13, and evidence for genetic heterogeneity. Moreira MC, Barbot C, Tachi N, Kozuka N, Mendonça P, Barros J, Coutinho P, Sequeiros J, Koenig M. Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/Université Louis-Pasteur, Illkirch, C.U. de Strasbourg, France. Abstract Ataxia with oculomotor apraxia (AOA) is characterized by early-onset cerebellar ataxia, ocular apraxia, early areflexia, late peripheral neuropathy, slow progression, severe motor handicap, and absence of both telangiectasias and immunodeficiency. We studied 13 Portuguese families with AOA and found that the two largest families show linkage to 9p, with LOD scores of 4.13 and 3.82, respectively, at a recombination fraction of 0. These and three smaller families, all from northern Portugal, showed homozygosity and haplotype sharing over a 2-cM region on 9p13, demonstrating the existence of both a founding event and linkage to this locus, AOA1, in the five families. Three other families were excluded from this locus, demonstrating nonallelic heterogeneity in AOA. Early-onset cerebellar ataxia with hypoalbuminemia (EOCA-HA), so far described only in Japan, is characterized by marked cerebellar atrophy, peripheral neuropathy, mental retardation, and, occasionally, oculomotor apraxia. Two unrelated Japanese families with EOCA-HA were analyzed and appeared to show linkage to the AOA1 locus. Subsequently, hypoalbuminemia was found in all five Portuguese patients with AOA1 with a long disease duration, suggesting that AOA1 and EOCA-HA correspond to the same entity that accounts for a significant proportion of all recessive ataxias. The narrow localization of AOA1 should prompt the identification of the defective gene. PMID: 11170899 [PubMed - indexed for MEDLINE]PMCID: PMC1235299Free PMC Article Images from this publication.See all images (3) Free text Figure 1Simplified pedigrees of the families with AOA that show linkage to 9p13, and of family AOAP9. Markers are shown, from top to bottom, in their pter-qter order (from GeneMap'99). Haplotypes linked to the disease are boxed, and homozygosity in patients is shaded in gray. Distance (cM) to the previous m...Homozygosity Mapping of Portuguese and Japanese Forms of Ataxia-Oculomotor Apraxia to 9p13, and Evidence for Genetic HeterogeneityAm J Hum Genet. 2001 February;68(2):501-508.Figure 2Haplotypes in families AOAP1, -P4, -P5, -P7, -P11, and -P9 and in AOAJ1 and -J2. Homozygous alleles are indicated only once per family. Alleles homozygous by descent are in boldface. The shared haplotypes are boxed and shaded in gray. Alleles that might belong to the founding haplotypes are boxed wi...Homozygosity Mapping of Portuguese and Japanese Forms of Ataxia-Oculomotor Apraxia to 9p13, and Evidence for Genetic HeterogeneityAm J Hum Genet. 2001 February;68(2):501-508.Figure 3Geographical distribution, on the Portuguese mainland, of families with AOA. Districts where the survey is already completed are shaded in gray. Family AOAP13 is not represented, because of its African (Cabo Verde) origin. The three families in the Braga region that show linkage to 9p are AOAP4, -P7...Homozygosity Mapping of Portuguese and Japanese Forms of Ataxia-Oculomotor Apraxia to 9p13, and Evidence for Genetic HeterogeneityAm J Hum Genet. 2001 February;68(2):501-508.
- Liver Transplantation Prevents Progressive Neurological Impairment in ArgininemiaPublication . Santos-Silva, E.; Cardoso, M.; Vilarinho, L.; Medina, M.; Barbot, C.; Martins, E.Argininemia is a rare hereditary disease due to a deficiency of hepatic arginase, which is the last enzyme of the urea cycle and hydrolyzes arginine to ornithine and urea. The onset of the disease is usually in childhood, and clinical manifestations include progressive spastic paraparesis and mental retardation. Liver involvement is less frequent and usually not as severe as observed in other UCDs. For this reason, and because usually there is a major neurological disease at diagnosis, patients with argininemia are rarely considered as candidates for OLT despite its capacity to replace the deficient enzyme by an active one. We report on long-term follow-up of two patients with argininemia. Patient 1 was diagnosed by the age of 20 months and despite appropriate conventional treatment progressed to spastic paraparesis with marked limp. OLT was performed at 10 years of age with normalization of plasmatic arginine levels and guanidino compounds. Ten years post-OLT, under free diet, there is no progression of neurological lesions. The second patient (previously reported by our group) was diagnosed at 2 months of age, during a neonatal cholestasis workup study. OLT was performed at the age of 7 years, due to liver cirrhosis with portal hypertension, in the absence of neurological lesions and an almost-normal brain MRI. After OLT, under free diet, there was normalization of plasmatic arginine levels and guanidino compounds. Twelve years post-OLT, she presents a normal neurological examination. We conclude that OLT prevents progressive neurological impairment in argininemia and should be considered when appropriate conventional treatment fails.
- Recessive ataxia with ocular apraxia: review of 22 Portuguese patients.Publication . Barbot, C.; Coutinho, P.; Chorão, R.; Ferreira, C.; Barros, J.; Fineza, I.; Dias, K.; Monteiro, J.; Guimarães, A.; Mendonça, P.; Moreira, M.; Sequeiros, J.Abstract BACKGROUND: The recessive ataxias are a heterogeneous group of neurodegenerative disorders characterized by cerebellar ataxia associated with a number of different neurologic, ophthalmologic, or general signs. They are often difficult to classify in clinical terms, except for Friedreich ataxia, ataxia-telangiectasia, and a relatively small group of rare conditions for which the molecular basis has already been defined. OBJECTIVES: To study the clinical presentation and to define diagnostic criteria in a group of Portuguese patients with ataxia and ocular apraxia, an autosomal recessive form without the essential clinical and laboratory features of ataxia-telangiectasia. PATIENTS AND METHODS: We reviewed 22 patients in 11 kindreds, identified through a systematic survey of hereditary ataxias being conducted in Portugal. RESULTS: Age at onset ranged from 1 to 15 years, with a mean of 4.7 years. The duration of symptoms at the time of last examination varied from 5 to 58 years. All patients presented with progressive cerebellar ataxia, the characteristic ocular apraxia, and a peripheral neuropathy. Associated neurologic signs included dystonia, scoliosis, and pes cavus. Magnetic resonance imaging was performed in 16 patients, all of whom showed cerebellar atrophy. CONCLUSIONS: Ataxia with ocular apraxia may be more frequent than postulated before, and may be identified clinically using the following criteria: (1) autosomal recessive transmission; (2) early onset (for most patients in early childhood); (3) combination of cerebellar ataxia, ocular apraxia, and early areflexia, with later appearance of the full picture of peripheral neuropathy; (4) absence of mental retardation, telangiectasia, and immunodeficiency; and (5) the possibility of a long survival, although with severe motor handicap.
- Senataxin, the ortholog of a yeast RNA helicase, is mutant in ataxia-ocular apraxia 2.Publication . Moreira, M.C.; Klur, S.; Watanabe, M.; Németh, A.H.; Le Ber, I.; Moniz, J.C.; Tranchant, C.; Aubourg, P.; Tazir, M.; Schöls, L.; Pandolfo, M.; Schulz, J.B.; Pouget, J.; Calvas, P.; Shizuka-Ikeda, M.; Shoji, M.; Tanaka, M.; Izatt, L.; Shaw, C.E.; M'Zahem, A.; Dunne, E.; Bomont, P.; Benhassine, T.; Bouslam, N.; Stevanin, G.; Brice, A.; Guimarães, J.; Mendonça, P.; Barbot, C.; Coutinho, P.; Sequeiros, J.; Dürr, A.; Warter, J.M.; Koenig, M.Nat Genet. 2004 Mar;36(3):225-7. Epub 2004 Feb 8. Senataxin, the ortholog of a yeast RNA helicase, is mutant in ataxia-ocular apraxia 2. Moreira MC, Klur S, Watanabe M, Németh AH, Le Ber I, Moniz JC, Tranchant C, Aubourg P, Tazir M, Schöls L, Pandolfo M, Schulz JB, Pouget J, Calvas P, Shizuka-Ikeda M, Shoji M, Tanaka M, Izatt L, Shaw CE, M'Zahem A, Dunne E, Bomont P, Benhassine T, Bouslam N, Stevanin G, Brice A, Guimarães J, Mendonça P, Barbot C, Coutinho P, Sequeiros J, Dürr A, Warter JM, Koenig M. IGBMC (Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, ULP) 67404 Illkirch, C.U. de Strasbourg, France. Abstract Ataxia-ocular apraxia 2 (AOA2) was recently identified as a new autosomal recessive ataxia. We have now identified causative mutations in 15 families, which allows us to clinically define this entity by onset between 10 and 22 years, cerebellar atrophy, axonal sensorimotor neuropathy, oculomotor apraxia and elevated alpha-fetoprotein (AFP). Ten of the fifteen mutations cause premature termination of a large DEAxQ-box helicase, the human ortholog of yeast Sen1p, involved in RNA maturation and termination. PMID: 14770181 [PubMed - indexed for MEDLINE]
- Vómitos Cíclicos / Acidúria Glutárica tipo II - Caso ClínicoPublication . Sarmento, A.; Cardoso, M.; Teixeira, F.; Barbot, C.; Martins, E.RESUMO O síndrome de vómitos cíclicos caracteriza-se por episódios recorrentes de vómitos que persistem durante horas ou dias com intervalo de normalidade entre eles. O seu diagnóstico baseia-se na exclusão de outras patologias: alterações do aparelho gastrointestinal, lesão neurológica ocupante de espaço e doenças metabólicas. Apresenta-se o caso de uma adolescente de 13 anos, com má evolução staturoponderal, desenvolvimento psicomotor adequado e referência a vómitos recorrentes desde os 2 anos. Em alguns destes episódios documentou- se hipoglicemia, acidose metabólica, cetonúria marcada e aumento das transaminases hepáticas. O estudo metabólico efectuado aos 11 anos mostrou alterações na cromatografia dos ácidos orgânicos urinários com aumento do ácido β-hidroxiglutárico e acidúria dicarboxílica. Na repetição deste estudo estas alterações mantiveram-se. As hipóteses de diagnóstico incluíram défices da β-oxidação dos ácidos gordos, dos transportadores de electrões (acidúria glutárica tipo II), da cadeia mitocondrial e acidúria D2 ou L2-hidroxiglutárica. O perfil das acilcarnitinas plasmáticas e o estudo da cadeia respiratória no músculo revelaram-se normais. O doseamento do isómero D do ácido 2- hidroxiglutárico na urina, plasma e LCR mostrou-se elevado. Este último resultado seria compatível com acidúria D2- hidroxiglutárica, mas o estudo da β-oxidação em fibroblastos mostra diminuição da actividade do ETF (electron transfer flavoprotein), o que permitiu o diagnóstico definitivo de acidúria glutárica tipo II. Esta é uma doença rara, caracterizada não só por bloqueio da oxidação dos ácidos gordos, mas também por alterações na oxidação de aminoácidos de cadeia ramificada e degradação da lisina, triptofano e hidroxilisina. Tem clínica e gravidade variáveis. O caso referido representa um fenótipo de sintomatologia ligeira, essencialmente gastrointestinal, sem envolvimento major do sistema nervoso central, coração e músculo. ABSTRACT Cyclic vomiting syndrome is characterized by recurrent vomiting that last hours or days without symptoms between those episodes. The diagnosis is made when others disorders are excluded, like: abnormalities of gastrointestinal tract, neurological space-occupying lesions and metabolic disorders. We present a 13 years old girl with normal psychomotor development, weight loss and recurrent vomiting since two years old. During decompensation periods she had metabolic acidosis, severe ketonuria and increased transaminases levels in serum. Metabolic investigation performed at 11 years old exhibits changes on organic acid profiles, with marked increased excretion of D-2-hydroxyglutaric acid in urine and dicarboxylic aciduria. Forward analyses show the same. The differential diagnoses were disorders of β-oxidation, defects in pathway for transferring electrons, defects of the mitochondrial respiratory chain and D-2 or L-2-hydroxyglutaric aciduria. Analysis of plasma acylcarnitine profiles and study of mitochondrial respiratory chain in skeletal muscle were normal. The separation of D and L stereisomers of 2-hydroxyglutaric acid showed an increased of the D form in urine, plasma and CSF. The study of mitochondrial β-oxidation in fibroblasts showed a deficiency in ETF (electron transfer flavoprotein) and final diagnosis of Glutaric Aciduria type II. This is a rare disorder with defects not only in fatty acid oxidation, but also in the oxidation of branched-chain amino acids and degradation of lysine, tryptophan and hydroxylysine. Their clinical spectrum and prognosis are variable. The case reported show a phenotype with mild symptoms, mainly gastrointestinal symptoms, without major envelopment of central nervous system and skeletal muscle.