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A Fenilcetonúria Clássica é causada pela deficiência da enzima hepática fenilalaninahidroxilase. Se não diagnosticada e tratada precocemente, causa retardo mental. O objetivo deste estudo foi identificar indivíduos submetidos à triagem neonatal no Rio Grande do Sul entre 1986 e 2003, com teste positivo para hiperfenilalaninemia, estimar a prevalência de hiperfenilalaninemias, verificar níveis de controle e correlacionar os anos de realização do teste, início do tratamento, evolução e quadro clínico. Métodos: Casos de hiperfenilalaninemia foram identificados nos laboratórios e clínicas de tratamento. Foi aplicado questionário, contendo variáveis demográficas e sobre a patologia, o desenvolvimento infantil, a escolaridade, o aconselhamento genético e o rastreamento neonatal. Foram avaliados pacientes entre 6 meses e 16 anos de idade. Na análise estatística, utilizou-se o teste do qui quadrado e ANOVA para avaliar a associação entre ano do diagnóstico e controle de fenilalanina e regressão logística para avaliar o efeito conjunto de idade do diagnóstico e controle de fenilalanina sobre o atraso no desenvolvimento. Resultados: De 1986 a 2003, 418 crianças apresentaram teste positivo para fenilalanina. Destes, 351 (84,0%) apresentaram resultados normais na segunda amostra, 58 (13,9%) foram considerados portadores de hiperfenilalaninemia e 9 (2,1%) tiveram o seguimento perdido. A cobertura do programa foi de 50%. Sobre o aconselhamento genético, 39 entrevistados (72,2%) responderam não saber, não lembrar ou deram respostas incorretas. Conclusão: Não se observou tendência histórica do diagnóstico ter se tornado mais precoce ou do controle laboratorial ter se tornado melhor. O controle bioquímico da fenilalanina não dependeu da precocidade do diagnóstico e sim, da idade dos pacientes. Classical phenylketonuria is caused by deficiency of the hepatic enzyme phenylalanine hydroxylase. If not diagnosed and treated early, it causes mental retardation. The aim of this study was to identify patients who underwent neonatal screening in Rio Grande do Sul between 1986 and 2003 and tested positive for hyperphenylalaninemia, to estimate the prevalence of hyperphenyl-alaninaemias, to check the levels of control, and to correlate the years of testing, initiation of treatment, evolution and clinical picture. Methods: Cases of hyperphenylalaninemia were identified in laboratories and treatment clinics. A questionnaire was administered containing demographic variables and about the pathology, child development, education, genetic counseling and neonatal screening. We evaluated patients between 6 months and 16 years of age. The statistical analysis used the chi-square test and ANOVA to assess the association between year of diagnosis and control of phenylalanine and logistic regression to assess the combined effect of age at diagnosis and control of phenylalanine on the developmental delay. Results: From 1986 to 2003, 418 children tested positive for phenylalanine. Of these, 351 (84.0%) had normal results in the second sample, 58 (13.9%) were considered with hyperphenylalaninemia, and 9 (2.1%) were lost for follow-up . The coverage of the program was 50%. Concerning genetic counseling, 39 respondents (72.2%) reported not knowing, not remembering or gave incorrect answers. Conclusion: There was no historical trend of diagnosis having become earlier or of laboratory control having improved. The biochemical control of phenylalanine was dependent on patient age rather than on early diagnosis.

Background. Machado-Joseph disease (MJD) is an autosomal dominant neurodegenerative disorder of late onset, caused by a (CAG)n expansion at the ATXN3 gene (14q32.1). Variation in age-at-onset is partially explained by the size of the (CAG)n tract in expanded alleles. The remaining variation should be the product of other factors, namely modifier genes. The genotype at the APOE locus has been described as a possible modifier in different neurological disorders, namely Parkinson (PD) and Huntington disease (HD). In the CNS, apolipoprotein E constitutes an important mediator of cholesterol transport/metabolism, which is essential for synaptic integrity and neuronal function. Objective. To investigate a modulating effect of the APOE polymorphism on age-at-onset of MJD. Design and Subjects. The APOE polymorphism was typed in a series of 192 MJD patients. Results. Cases with the ε2/ε3 genotype presented an earlier onset, when compared with those with ε3/ε3 or ε3/ε4. In this series of patients, the presence of an APOE ε2 allele implies a decrease of nearly 5 years in the age-at-onset. When combining, in a general linear model, several other predictors, namely the presence/absence of the APOE ε2 allele, with the size of the (CAG)n in expanded alleles, the model was significantly improved and the explanation of onset variance was raised from 59.8% to 66.5%. Furthermore, the presence of the ε2 allele was associated with an onset below 39 years (OR=5.00; 95% CI: 1.18-21.14). Conclusions. These findings indicate that the polymorphism at the APOE gene plays a role as a genetic modifier of MJD phenotype., Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BPD/63121/2009, SFRH/BPD/38659/2007, M3.1.3/F/004/2009, “Secretaria Regional da Ciência, Tecnologia e Equipamentos”., Fundação para a Ciência e a Tecnologia (FCT) - “Transcriptional variation of the ATXN3 gene as modulator of the clinical heterogeneity in Machado-Joseph disease (MJD)” (PIC/IC/83074/2007), Institute of Biotechnology and Biomedicine (IBBA) - “High prevalence diseases in the Azores Islands” (M2.1.2/I/026/2008

Blackburn, Szostak e Greider responderam uma pergunta que assombrava há anos a biologia: como as terminações dos cromossomos são poupadas da erosão e dos rearranjos durante as divisões celulares? A própria pergunta é difícil de ser compreendida, sem revisarmos um pouco a história do conhecimento sobre os cromossomos. A descoberta de sua função rendeu um primeiro Prêmio Nobel a Thomas H Morgan em 1933. Um segundo e um terceiro premiados, Hermann Muller (1946) e Barbara McClintock (1983) subsequentemente descobririam que cromossomos “quebrados” eram instáveis e muito propensos a rearranjos. Mas Hermann Muller já notava que as pontas constitucionais dos cromossomos impediam ou dificultavam esses eventos danosos. Foi ele que as denominou de “telômeros” - do grego telos - término – e meros – parte.

As mucopolissacaridoses (MPS) são doenças genéticas raras causadas pela deficiência de enzimas lisossômicas específicas que afetam o catabolismo de glicosaminoglicanos (GAG). O acúmulo de GAG em vários órgãos e tecidos nos pacientes afetados pelas MPS resulta em uma série de sinais e sintomas, integrantes de um quadro clínico multissistêmico que compromete ossos e articulações, vias respiratórias, sistema cardiovascular e muitos outros órgãos e tecidos, incluindo, em alguns casos, as funções cognitivas. Já foram identificados 11 defeitos enzimáticos que causam sete tipos diferentes de MPS. Antes do advento de terapias dirigidas para a restauração da atividade da enzima deficiente, o tratamento das MPS tinha como principal foco a prevenção e o cuidado das complicações, aspecto ainda bastante importante no manejo desses pacientes. Na década de 80 foi proposto o tratamento das MPS com transplante de medula óssea/transplante de células tronco hematopoiéticas (TMO/TCTH) e na década de 90 começou o desenvolvimento da Terapia de Reposição Enzimática (TRE), que se tornou uma realidade aprovada para uso clínico nas MPS I, II e VI na primeira década do século 21. Os autores deste trabalho têm a convicção de que um melhor futuro para os pacientes afetados pelas MPS depende da identificação, compreensão e manejo adequado das manifestações multissistêmicas dessas doenças, incluindo medidas de suporte (que devem fazer parte da assistência multidisciplinar regular destes pacientes) e terapias específicas. Embora a inibição da síntese de GAG e o resgate da atividade enzimática com moléculas pequenas também possam vir a ter um papel no manejo das MPS, o grande avanço disponível no momento é a TRE intravenosa. A TRE permitiu modificar radicalmente o panorama do tratamento das mucopolissacaridoses I, II e VI na última década, sendo que ainda pode estender seus benefícios em breve para a MPS IV A (cuja TRE já está em desenvolvimento clínico), com perspectivas para o tratamento da MPS III A e do déficit cognitivo na MPS II através de administração da enzima diretamente no sistema nervoso central (SNC). Um grande número de centros brasileiros, incluindo serviços de todas as regiões do país, já têm experiência com TRE para MPS I, II e VI. Essa experiência foi adquirida não só com o tratamento de pacientes como também com a participação de alguns grupos em ensaios clínicos envolvendo TRE para essas condições. Somados os três tipos de MPS, mais de 250 pacientes já foram tratados com TRE em nosso país. A experiência dos profissionais brasileiros, somada aos dados disponíveis na literatura internacional, permitiu elaborar este documento, produzido com o objetivo de reunir e harmonizar as informações disponíveis sobre o tratamento destas doenças graves e progressivas, mas que, felizmente, são hoje tratáveis, uma realidade que traz novas perspectivas para os pacientes brasileiros afetados por essas condições. Mucopolysaccharidoses (MPS) are rare genetic diseases caused by deficiency of specific lysosomal enzymes that affect catabolism of glycosaminoglycans (GAG). Accumulation of GAG in various organs and tissues in MPS patients results in a series of signs and symptoms, producing a multisystemic condition affecting bones and joints, the respiratory and cardiovascular systems and many other organs and tissues, including in some cases, cognitive performance. So far, eleven enzyme defects that cause seven different types of MPS have been identified. Before introduction of therapies to restore deficient enzyme activity, treatment of MPS focused primnarily on prevention and care of complications, still a very important aspect in the management of these patients. In the 80’s treatment of MPS with bone marrow transplantation/hematopoietic stem cells transplantation (BMT/ HSCT) was proposed and in the 90’s, enzyme replacement therapy (ERT),began to be developed and was approved for clinical use in MPS I, II and VI in the first decade of the 21st century. The authors of this paper are convinced that a better future for patients affected by mucopolysaccharidoses depends upon identifying, understanding and appropriately managing the multisystemic manifestations of these diseases. This includes the provision of support measures (which should be part of regular multidisciplinary care of these patients) and of specific therapies. Although inhibition of synthesis of GAG and the recovery of enzyme activity with small molecules also may play a role in the management of MPS, the breakthrough is the currently available intravenous ERT. ERT radically changed the setting for treatment of mucopolysaccharidosis I, II and VI in the last decade., Benefits can even be extended soon to MPS IV A (ERT for this condition is already in clinical development), with prediction for treatment of MPS III A and the cognitive deficit in MPS II by administration of the enzyme directly into the central nervous system (CNS). A large number of Brazilian services, from all regions of the country, already have experience with ERT for MPS I, II and VI. This experience was gained not only by treating patients but also with the participation of some groups in clinical trials involving ERT for these conditions. Summing up the three types of MPS, more than 250 patients have already been treated with ERT in Brazil. The experience of professionals coupled to the data available in international literature, allowed us to elaborate this document, produced with the goal of bringing together and harmonize the information available for the treatment of these severe and progressive diseases, which, fortunately, are now treatable, a situation which bring new perspectives for Brazilian patients, affected by these conditions.

Mucopolysaccharidoses (MPS) are rare genetic diseases caused by the deficiency of one of the lysosomal enzymes involved in the glycosaminoglycan (GAG) breakdown pathway. This metabolic block leads to the accumulation of GAG in various organs and tissues of the affected patients, resulting in a multisystemic clinical picture, sometimes including cognitive impairment. Until the beginning of the XXI century, treatment was mainly supportive. Bone marrow transplantation improved the natural course of the disease in some types of MPS, but the morbidity and mortality restricted its use to selected cases. The identification of the genes involved, the new molecular biology tools and the availability of animal models made it possible to develop specific enzyme replacement therapies (ERT) for these diseases. At present, a great number of Brazilian medical centers from all regions of the country have experience with ERT for MPS I, II, and VI, acquired not only through patient treatment but also in clinical trials. Taking the three types of MPS together, over 200 patients have been treated with ERT in our country. This document summarizes the experience of the professionals involved, along with the data available in the international literature, bringing together and harmonizing the information available on the management of these severe and progressive diseases, thus disclosing new prospects for Brazilian patients affected by these conditions.

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Background: Machado-Joseph disease (MJD SCA3), a spinocerebellar ataxia related to expansion of a CAG tract, has already been related to anticipation and meiotic drift. However, fitness of MJD carriers has been little studied. Objective: To analyze genetic fitness of MJD patients, comparing them to their unaffected relatives and to the general population (GP) of origin. Subjects and methods: 182 informants, belonging to 82 MJD families, agreed to participate in the study. Informants supplied data about 828 MJD patients. Number of children (NC), gender, age, school attainment, menarche and menopause were compared between general and emeritus (older than 45 years of age or deceased) groups. Results: Mean NC of the GP and of MJD patients were respectively 1.90 and 2.93± 2.3 (p = 0.0037). Comparisons within families also showed differences: the mean NC of unaffected and affected emeritus MJD women were, respectively, 2.68 and 3.89 (p = 0.0037). Affected MJD women had earlier mean ages at the delivery of their first child and menopause (p < 0.011 and 0.07, respectively). Among affected women those who did not have children had larger CAG tracts than those who had children (p < 0.05). Conclusion: MJD enhances the fitness of its carriers, and this phenomenon seems to have a biological basis.

The neuronal ceroid lipofuscinoses (NCL) are a group of inherited progressive neurodegenerative disorders with presentation from infancy to adulthood. Three main childhood forms can be established on the basis of age of onset, clinical course, and ultrastructural morphology: infantile (INCL), late infantile (LINCL), and juvenile (JNCL). Several variant subtypes have been described. Genetic and biochemical analysis are helping to better understand, diagnose and classify these disorders. We report on clinical, neurophysiological, neuroradiological, and morphological data from 17 patients with different forms (infantile, late infantile, and juvenile ) of neuronal ceroid lipofuscinoses (NCL) evaluated at Hospital de Clínicas de Porto Alegre, Southern Brazil, during 6 years (1992-1997). Seven cases were infantile; 5 were late infantile; and 5 were juvenile NCL. Gender ratio was male:female, 11:6. Age at presentation varied from 2-24 months for INCL; 2,5 to 5 years for LINCL ; and 4-10 years for the JNCL cases. Seizures (6 patients) and psychomotor retardation (1 patient) were the initial symptoms in the INCL group. All the patients in the group of LINCL had the usual findings. JNCL patients manifested different initial symptoms, although tending to follow a similar clinical picture within familial cases. Epidemiological data on the prevalence of NCLs in Brazil are not available, we expect this series of cases to contribute to further research in our population. As lipofuscinoses ceroides neuronais (LCN) constituem um grupo de desordens neurodegenerativas, progressivas e de origem genética. O início dos sintomas varia desde a infancia até a vida adulta. Três principais formas infantis são estabelecidas com base na idade de início, evolução clínica e morfologia celular, através de microscopia eletrônica: infantil (LCNI), infantil tardia (LCNIT) e juvenil (LCNJ). Vários subtipos têm sido descritos. Investigação genética e bioquímica vem possibilitando melhor entendimento, diagnóstico e classificação destas desordens. Relatamos achados clínicos, neurofisiológicos, neurorradiológicos e morfológicos de 17 pacientes com diferentes formas de LCN (infantil, infantil tardia e juvenil), avaliados no Hospital de Clínicas de Porto Alegre, durante 6 anos (1992-1997). Tivemos 7 diagnósticos de LCNI, 5 de LCNIT, e 5 casos de LCNJ. Proporção entre gêneros foi 11:6 (masculino:feminino). Convulsões (6 pacientes) e retardo psicomotor (1 paciente) foram os sintomas iniciais no grupo LCNI. Todos os casos de LCNIT tiveram achados usuais. Os pacientes com LCNJ apresentaram diferentes sintomas iniciais, embora tendendo a similaridade em casos familiais. Não há dados epidemiológicos sobre LCN no Brasil. Esperamos que esta serie de casos contribua para maior investigação deste grupo de desordens em nossa população.

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A doença de Huntington (DH) está associada a expansões da seqüência repetitiva de trinucleotídeos CAG no gene HD. Através de análise do número de repetições CAG em indivíduos brasileiros, amostras de 92 indivíduos-controle não afetados pela DH, 44 pacientes com DH e 40 indivíduos de 6 famílias com a DH, demonstrou-se a presença de repetições de 7 até 33 trinucleotídeos CAG nos indivíduos-controle e de 39 até 88 nos alelos mutados dos indivíduos afetados. Foi constatada relação inversa entre a idade de manifestação dos primeiros sintomas da doença e o tamanho do fragmento encontrado. Também foi observado que o número de casos em que ocorrem expansões do trinucleotídeo foi maior quando o pai transmite o alelo mutado do que quando a mãe o transmite. Os dados gerados com este estudo têm importância significativa para a compreensão da etiologia, incidência, diagnóstico, prognóstico e tratamento dos pacientes com DH na população brasileira. O conhecimento da base genética desta doença na população brasileira permitirá um aconselhamento genético mais eficiente às famílias em risco. Huntington disease (HD) is associated with expansions of a CAG trinucleotide repeat in the HD gene. Accurate measurement of a specific CAG repeat sequence in the HD gene in 92 Brazilian controls without HD, 44 Brazilian subjects with clinical findings suggestive of HD and 40 individuals from 6 putative HD families, showed a range from 7 to 33 repeats in normal subjects and 39 to 88 repeats in affected subjects. A trend between early age at onset of first symptoms and increasing number of repeats was seen. Major increase of repeat size through paternal inheritance than through maternal inheritance was observed. Data generated from this study may have significant implications for the etiology, knowledge of the incidence, diagnosis, prognosis, genetic counseling and treatment of HD Brazilian patients.

The neuronal ceroid lipofuscinoses (NCL) are a group of inherited progressive neurodegenerative disorders with presentation from infancy to adulthood. Three main childhood forms can be established on the basis of age of onset, clinical course, and ultrastructural morphology: infantile (INCL), late infantile (LINCL), and juvenile (JNCL). Several variant subtypes have been described. Genetic and biochemical analysis are helping to better understand, diagnose and classify these disorders. We report on clinical, neurophysiological, neuroradiological, and morphological data from 17 patients with different forms (infantile, late infantile, and juvenile ) of neuronal ceroid lipofuscinoses (NCL) evaluated at Hospital de Clínicas de Porto Alegre, Southern Brazil, during 6 years (1992-1997). Seven cases were infantile; 5 were late infantile; and 5 were juvenile NCL. Gender ratio was male:female, 11:6. Age at presentation varied from 2-24 months for INCL; 2,5 to 5 years for LINCL ; and 4-10 years for the JNCL cases. Seizures (6 patients) and psychomotor retardation (1 patient) were the initial symptoms in the INCL group. All the patients in the group of LINCL had the usual findings. JNCL patients manifested different initial symptoms, although tending to follow a similar clinical picture within familial cases. Epidemiological data on the prevalence of NCLs in Brazil are not available, we expect this series of cases to contribute to further research in our population.

Friedreich ataxia (FRDA), the most common autosomal recessive ataxia, is caused in 94% of cases by homozygous expansions of an unstable GAA repeat localised in intron 1 of the X25 gene. We have investigated this mutation in five Brazilian patients: four with typical FRDA findings and one patient with atypical manifestations, who was considered to have some other form of cerebellar ataxia with retained reflexes. The GAA expansion was detected in all these patients. The confirmation of FRDA diagnosis in the atypical case may be pointing out, as in other reports, that clinical spectrum of Friedreich's ataxia is broader than previously recognised and includes cases with intact tendon reflexes. A ataxia de Friedreich (FRDA) é a mais frequente das ataxias com herança autossômica recessiva. Em 94 % dos casos, é causada por uma expansão homozigota instável da repetição de trinucleotídeos GAA, localizada no primeiro íntron do gene X25. Esta mutação foi investigada em cinco pacientes brasileiros: quatro com quadro clínico típico de FRDA e um paciente com manifestações atípicas, cujo diagnóstico prévio era o de alguma outra forma de ataxia cerebelar com preservação de reflexos. A investigação foi positiva nos cinco casos. A confirmação do diagnóstico de FRDA no paciente com quadro atípico, assim como em outros casos semelhantes já relatados na literatura, sugere que o espectro de manifestações clínicas da FRDA seja mais amplo do que o classicamente reconhecido, incluindo casos com preservação de reflexos.

Friedreich ataxia (FRDA), the most common autosomal recessive ataxia, is caused in 94% of cases by homozygous expansions of an unstable GAA repeat localised in intron 1 of the X25 gene. We have investigated this mutation in five Brazilian patients: four with typical FRDA findings and one patient with atypical manifestations, who was considered to have some other form of cerebellar ataxia with retained reflexes. The GAA expansion was detected in all these patients. The confirmation of FRDA diagnosis in the atypical case may be pointing out, as in other reports, that clinical spectrum of Friedreich’s ataxia is broader than previously recognised and includes cases with intact tendon reflexes.

Relata-se aqui o manejo terapêutico realizado em um paciente portador da Doença da Urina do Xarope de Bordo, com diagnóstico e encaminhamento tardios (2 e 5 meses). Uma vez que o paciente apresentava níveis extremamente elevados de leucina no plasma (1956 micromoles/L, para um normal de até 77), houve necessidade de se realizar uma glicoinsulinoterapia nos primeiros dias de tratamento, seguida posteriormente da dieta específica para esta doença (hipercalórica e restrita em aminoácidos de cadeia ramificada). Além de uma breve revisão sobre o assunto, os autores enfatizam as grandes dificuldades de se realizar um diagnóstico precoce e de se obter fórmulas alimentares específicas para esta doença, no Brasil. We report here the treatment and poor outcome of a case of Maple Syrup Urine Disease with late diagnosis and retrieval (2 and 5 months, respectively). As the proband had quite high levels of plasmatic leucine (1956 micromol/L for a normal upper limit of 77), we started immediately with a gluco-insulin therapy to produce anabolism in the infant. When leucine has fallen to 275,3 micromol/L, we instituted feeding with branched chain amino acid-free protein and high energy from carbohydrates. After reviewing briefly the clinical, biochemical and therapeutic aspects of this disorder, we comment on the great difficulties of making early diagnosis and of obtaining the specific dietetic formulas to Maple Syrup Urine Disease, in Brazil.