Spinocerebellar ataxias: microsatellite and allele frequency in unaffected and affected individuals / Ataxias espinocerebelares: freqüência de alelos e microsatélites em indivíduos normais e afetados

The diagnosis and incidence of spinocerebelar ataxias (SCA) is sometimes difficult to analyze due the overlap of phenotypes subtypes and are disorders of mutations caused by CAG trinucleotide repeat expansion. To investigate the incidence of the SCA in Southern Brazil, we analyzed the trinucleotide repeats (CAG)n at the SCA1, SCA2, SCA3, SCA6 and SCA7 loci to identify allele size ranges and frequencies. We examined blood sample from 154 asymptomatic blood donors and 115 individuals with progressive ataxias. PCR products were submitted to capillary electrophoresis. In the blood donors, the ranges of the five loci were: SCA1, 19 to 36 (CAG)n; SCA2, 6 to 28 (CAG)n; SCA3, 12 to 34 (CAG)n; SCA6, 2 to 13 (CAG)n; and SCA7, 2 to 10 (CAG)n. No deviations from Hardy-Weinberg equilibrium were detected. In the ataxia group, we found (CAG)n above the range of the asymptomatic blood donors in SCA3 (21.74 percent) followed by SCA2 (5.22 percent), SCA7 (2.61 percent), SCA6 (0.87 percent), and no cases of SCA1. The remaining 80 cases (69.56 percent) have different diagnoses from the type here studied. These data defined the alleles and their frequencies, as well as demonstrated their stability in the population not affected. The molecular diagnosis test confirmed the clinical diagnosis in 28/45 cases and classified another 7/70 from the clinical unclassified ataxias group.

A incidência e o diagnóstico das ataxias espinocerebelares (SCA) é algumas vezes difícil de avaliar devido a sobreposição dos diversos subtipos e por algumas serem devido a mutações das expansões do mesmo trinucleotídeo CAG. Para investigar a incidências das SCA no sul do Brasil, analisamos as repetições do trinucleotídeo (CAG)n nos loci das SCA1, SCA2, SCA3, SCA6 e SCA7, a fim de identificar os seus limites e freqüência. Examinamos o sangue de 154 doadores de sangue assintomáticos e 115 pacientes com ataxias progressivas. O produto do PCR do sangue foi submetido a eletroforese capilar. Nos doadores de sangue, as expansões encontradas nos cinco loci foram: SCA1, 19 a 36 (CAG)n; SCA2, 6 a 28 (CAG)n; SCA3, 12 a 34 (CAG)n; SCA6, 2 a 13 (CAG)n; and SCA7, 2 a 10 (CAG)n. Não foi detectado desequilíbrio na equação de Hardy-Weinberg. No grupo das ataxias encontramos repetições CAG acima das freqüências dos doadores de sangue na SCA3 (21,7 por cento), seguido da SCA2 (5,22 por cento), SCA7 (2,61 por cento), SCA6 (0,8 por cento) e não foi encontrado nenhum caso de SCA1. Os 80 casos restantes (69,56 por cento) devem ter uma forma de ataxia diferente das aqui estudadas. Esses dados definem os alelos e suas freqüências, bem como demonstram a sua estabilidade na população não afetada. O diagnóstico molecular confirmou o diagnóstico clínico em 28/45 dos casos e permitiu classificar outros 7/70 que pertenciam ao grupo de ataxias clinicamente não classificadas.

MELAS: clinical features, muscle biopsy and molecular genetics.

OBJECTIVE: The aim of the study was to analyze a series of Brazilian patients suffering from MELAS. METHOD: Ten patients with MELAS were studied with correlation between clinical findings, laboratorial data, electrophysiology, histochemical and molecular features. RESULTS: Blood lactate was increased in eight patients. Brain image studies revealed a stroke-like pattern in all patients. Muscle biopsy showed ralled-red fibers (RRF) in 90% of patients on modified Gomori-trichrome and in 100% on succinate dehydrogenase stains. Cytochrome c oxidase stain analysis indicated deficient activity in one patient and subsarcolemmal accumulation in seven patients. Strongly succinate dehydrogenase-reactive blood vessels (SSV) occurred in six patients. The molecular analysis of tRNA (Leu(UUR)) gene by PCR/RLFP and direct sequencing showed the A3243G mutation on mtDNA in 4 patients. CONCLUSION: The muscle biopsy often confirmed the MELAS diagnosis by presence of RRF and SSV. Molecular analysis of tRNA(Leu(UUR)) gene should not be the only diagnostic criteria for MELAS.

MELAS: clinical features, muscle biopsy and molecular genetics / MELAS: manifestações clínicas, biópsia muscular e estudo molecular

OBJECTIVE: The aim of the study was to analyze a series of Brazilian patients suffering from MELAS. METHOD: Ten patients with MELAS were studied with correlation between clinical findings, laboratorial data, electrophysiology, histochemical and molecular features. RESULTS: Blood lactate was increased in eight patients. Brain image studies revealed a stroke-like pattern in all patients. Muscle biopsy showed ralled-red fibers (RRF) in 90 percent of patients on modified Gomori-trichrome and in 100 percent on succinate dehydrogenase stains. Cytochrome c oxidase stain analysis indicated deficient activity in one patient and subsarcolemmal accumulation in seven patients. Strongly succinate dehydrogenase-reactive blood vessels (SSV) occurred in six patients. The molecular analysis of tRNA Leu(UUR) gene by PCR/RLFP and direct sequencing showed the A3243G mutation on mtDNA in 4 patients. CONCLUSION: The muscle biopsy often confirmed the MELAS diagnosis by presence of RRF and SSV. Molecular analysis of tRNA Leu(UUR) gene should not be the only diagnostic criteria for MELAS.

OBJETIVO: O objetivo deste estudo foi analisar uma série de pacientes brasileiros portadores de MELAS. MÉTODO: Dez pacientes com MELAS foram estudados com correlação entre manifestações clínicas, alterações laboratoriais, estudo eletrofisiológico, histoquímico e molecular. RESULTADOS: O nível de lactato sérico estava aumentado em 8 pacientes. O estudo das imagens do crânio revelou padrão semelhante ao de AVC isquêmico em todos os pacientes. A biópsia muscular mostrou fibras rajadas vermelhas (RRF) em 90 por cento dos pacientes na coloração pelo tricrômio de Gomori modificado e em 100 por cento na reação histoquímica pela desidrogenase succicínica (SDH). A análise da coloração pela citocromo c oxidase indicou atividade deficiente em um paciente e acúmulo subsarcolemal em sete pacientes. Vasos com forte reação para SDH (SSV) ocorreram em seis pacientes. O estudo molecular do gene tRNA Leu(UUR) por PCR/RLFP e seqüenciamento direto mostrou a mutação A3243G no DNAmt de 4 pacientes. CONCLUSÃO: A biópsia muscular frequentemente confirma o diagnóstico de MELAS pela presença de RRF e SSV. O estudo molecular do gene tRNA Leu(UUR) não deve ser o único critério diagnóstico para MELAS.

Spinocerebellar ataxias: microsatellite and allele frequency in unaffected and affected individuals.

The diagnosis and incidence of spinocerebelar ataxias (SCA) is sometimes difficult to analyze due the overlap of phenotypes subtypes and are disorders of mutations caused by CAG trinucleotide repeat expansion. To investigate the incidence of the SCA in Southern Brazil, we analyzed the trinucleotide repeats (CAG)n at the SCA1, SCA2, SCA3, SCA6 and SCA7 loci to identify allele size ranges and frequencies. We examined blood sample from 154 asymptomatic blood donors and 115 individuals with progressive ataxias. PCR products were submitted to capillary electrophoresis. In the blood donors, the ranges of the five loci were: SCA1, 19 to 36 (CAG)n; SCA2, 6 to 28 (CAG)n; SCA3, 12 to 34 (CAG)n; SCA6, 2 to 13 (CAG)n; and SCA7, 2 to 10 (CAG)n. No deviations from Hardy-Weinberg equilibrium were detected. In the ataxia group, we found (CAG)n above the range of the asymptomatic blood donors in SCA3 (21.74%) followed by SCA2 (5.22%), SCA7 (2.61%), SCA6 (0.87%), and no cases of SCA1. The remaining 80 cases (69.56%) have different diagnoses from the type here studied. These data defined the alleles and their frequencies, as well as demonstrated their stability in the population not affected. The molecular diagnosis test confirmed the clinical diagnosis in 28/45 cases and classified another 7/70 from the clinical unclassified ataxias group.

Event-related potentials (P300) and neuropsychological assessment in boys exhibiting Duchenne muscular dystrophy.

OBJECTIVE: To examine auditory cognitive evoked potentials (P300 potentials) and neuropsychological dysfunction in patients with Duchenne muscular dystrophy (DMD). METHOD: P300 potentials and neuropsychological test results were obtained from 16 healthy control boys and 20 DMD patients. Full Intelligence Quotients (IQ) were estimated for patients and control group. Mean age was 9.5 years in the DMD patient group, and 10 years in the control group (p>0.05). RESULTS: The mean IQ values were 64.35 in the DMD patients and 82.68 in the control group (p=0.01). Mean P300 values were 347.6 in the DMD group and 337.4 in the control group (p=0.14). There was no significant correlation between parameters in each group. CONCLUSION: DMD patients showed a poor performance as evaluated by P300 potential compared to the control group, although the difference was not statistically significant. Systematic alterations in neuropsychological test results were found, the differences paralleling those detected in IQ.

Duchenne and Becker muscular dystrophy: a molecular and immunohistochemical approach.

Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are caused by mutations in the dystrophin gene. We studied 106 patients with a diagnosis of probable DMD/BMD by analyzing 20 exons of the dystrophin gene in their blood and, in some of the cases, by immunohistochemical assays for dystrophin in muscle biopsies. In 71.7% of the patients, deletions were found in at least one of the exons; 68% of these deletions were in the hot-spot 3' region. Deletions were found in 81.5% of the DMD cases and in all the BMD cases. The cases without deletions, which included the only woman in the study with DMD, had dystrophin deficiency. The symptomatic female carriers had no deletions but had abnormal dystrophin distribution in the sarcolemma (discontinuous immunostains). The following diagnoses were made for the remaining cases without deletions with the aid of a muscle biopsy: spinal muscular atrophy, congenital myopathy; sarcoglycan deficiency and unclassified limb-girdle muscular dystrophy. Dystrophin analysis by immunohistochemistry continues to be the most specific method for diagnosis of DMD/BMD and should be used when no exon deletions are found in the dystrophin gene in the blood.

Event-related potentials (P300) and neuropsychological assessment in boys exhibiting Duchenne muscular dystrophy

OBJECTIVE: To examine auditory cognitive evoked potentials (P300 potentials) and neuropsychological dysfunction in patients with Duchenne muscular dystrophy (DMD). METHOD: P300 potentials and neuropsychological test results were obtained from 16 healthy control boys and 20 DMD patients. Full Intelligence Quotients (IQ) were estimated for patients and control group. Mean age was 9.5 years in the DMD patient group, and 10 years in the control group (p>0.05). RESULTS: The mean IQ values were 64.35 in the DMD patients and 82.68 in the control group (p=0.01). Mean P300 values were 347.6 in the DMD group and 337.4 in the control group (p=0.14). There was no significant correlation between parameters in each group. CONCLUSION: DMD patients showed a poor performance as evaluated by P300 potential compared to the control group, although the difference was not statistically significant. Systematic alterations in neuropsychological test results were found, the differences paralleling those detected in IQ.

OBJETIVO: Avaliar potenciais evocados cognitivos auditivos (P300) e disfunções neuropsicológicas em pacientes com distrofia muscular de Duchenne (DMD). MÉTODO: Potenciais auditivos P300 e testes neuropsicológicos foram obtidos de 16 controles e 20 pacientes com DMD. Valores de quociente de inteligência (QI) foram estimados para os dois grupos. A media de idade foi de 9.5 anos no grupo DMD e 10 anos no grupo controle (p>0.05). RESULTADOS: Os valores médios de QI foram 64.35 no grupo DMD e 82.68 no grupo controle (p=0.01). A média de valores de P300 foi 347.6 no grupo DMD e 337.4 no grupo controle (p=0.14). Não houve correlação significativa entre os parâmetros em cada grupo. CONCLUSÃO: Os pacientes com DMD mostraram um pior desempenho nas testagens de P300 quando comparados com o grupo controle, embora a diferença não tenha apresentado diferença significativa. Alterações sistemáticas foram encontradas nos testes neuropsicológicos, correspondendo às alterações significativas vistas nos valores de QI.

Duchenne and Becker muscular dystrophy: a molecular and immunohistochemical approach

Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are caused by mutations in the dystrophin gene. We studied 106 patients with a diagnosis of probable DMD/BMD by analyzing 20 exons of the dystrophin gene in their blood and, in some of the cases, by immunohistochemical assays for dystrophin in muscle biopsies. In 71.7 percent of the patients, deletions were found in at least one of the exons; 68 percent of these deletions were in the hot-spot 3' region. Deletions were found in 81.5 percent of the DMD cases and in all the BMD cases. The cases without deletions, which included the only woman in the study with DMD, had dystrophin deficiency. The symptomatic female carriers had no deletions but had abnormal dystrophin distribution in the sarcolemma (discontinuous immunostains). The following diagnoses were made for the remaining cases without deletions with the aid of a muscle biopsy: spinal muscular atrophy, congenital myopathy; sarcoglycan deficiency and unclassified limb-girdle muscular dystrophy. Dystrophin analysis by immunohistochemistry continues to be the most specific method for diagnosis of DMD/BMD and should be used when no exon deletions are found in the dystrophin gene in the blood.

As distrofias musculares de Duchenne (DMD) e de Becker (DMB) são doenças causadas por mutação no gene da distrofina. Foram estudados 106 casos com a suspeita diagnóstica de DMD/BMD com a analise de 20 exons do gene da distrofina no sangue e biópsia muscular com imuno-histoquímica para distrofina em alguns casos. Em 71,7 por cento dos casos foi encontrada deleção em pelo menos um dos exons, sendo que 68 por cento das deleções localizam-se na região 3' hot spot. Foram encontradas deleções em 81,5 por cento dos DMD e em todos os BMD, sendo que os sem deleção tinham deficiência de distrofina, incluindo a mulher com DMD. As portadoras sintomáticas não tinham deleções mas anormalidades na distribuição da distrofina no sarcolema. Os outros casos sem deleção, com auxilio da biópsia muscular tiveram outros diagnósticos (atrofia muscular espinhal, miopatia congênita, deficiência de sarcoglicanos, distrofia de cinturas-membros sem classificação). A análise imuno-histoquímica para distrofina na biópsia muscular continua sendo o método mais específico para diagnóstico de DMD/DMB e deve ser utilizado quando não são encontradas deleções do gene da distrophina no sangue.

Small-subunit rRNA processome proteins are translationally regulated during differentiation of Trypanosoma cruzi.

We used differential display to select genes differentially expressed during differentiation of epimastigotes into metacyclic trypomastigotes in the protozoan parasite Trypanosoma cruzi. One of the selected clones had a sequence similar to that of the small-subunit (SSU) processome protein Sof1p, which is involved in rRNA processing. The corresponding T. cruzi protein, TcSof1, displayed a nuclear localization and is downregulated during metacyclogenesis. Heterologous RNA interference assays showed that depletion of this protein impaired growth but did not affect progression through the cell cycle, suggesting that ribosome synthesis regulation and the cell cycle are uncoupled in this parasite. Quantitative PCR (qPCR) assays of several SSU processome-specific genes in T. cruzi also showed that most of them were regulated posttranscriptionally. This process involves the accumulation of mRNA in the polysome fraction of metacyclic trypomastigotes, where TcSof1 cannot be detected. Metacyclic trypomastigote polysomes were purified and separated by sucrose gradient sedimentation. Northern blot analysis of the sucrose gradient fractions showed the association of TcSof1 mRNA with polysomes, confirming the qPCR data. The results suggest that the mechanism of regulation involves the blocking of translation elongation and/or termination.

Cystic fibrosis mutations R1162X and 2183AA G in two southern brazilian states

Realizou-se a análise de 79 pacientes provenientes do Sul do Brasil para duas mutaçöes raras da fibrose cística (CF), R1162X e 2183AA G; dentre estes pacientes, 49 eram nascidos no Estado do Paraná (PR) e 30 eram nascidos no Estado de Santa Catarina (SC). Para a mutaçäo 2183AA G, dois alelos foram detectados entre os pacientes de SC e um alelo entre os pacientes do PR. Quando estes pacientes foram classificados de acordo com a origem étnica, 14 por cento dos alelos detectados entre os pacientes de origem italiana eram portadores da mutaçäo R1162X e 7 por cento da mutaçäo 2183AA G. Estas mutaçöes, juntamente com a mutaçäo delta F508, também foram analisadas em uma amostra de 270 indivíduos normais de origem italiana näo-consangüíneos, os quais eram nascidos no Estado do PR. Nessa amostra foram detectados dois alelos delta F508 e um alelo 2183AA G. As freqüências das mutaçöes delta F508, R1162X e 2183AA G näo mostraram desvio estatístico significativo daquelas freqüências observadas no norte da Itália. Nossos resultados demonstram que é importante incluir estas mutaçöes no conjunto de mutaçöes a serem pesquisadas nos pacientes com FC do sul do Brasil, especialmente quando estes pacientes tiverem origem italiana.