Ataxia de Friedreich, revisión y actualización de la literatura con búsqueda sistemática de casos en Latinoamérica / Friedreich's ataxia, review and literature update with a systematic search for cases in Latin America

La Ataxia de Friedreich (AF) es una enfermedad neurodegenerativa autosómica recesiva con compromiso multisistémico. En esta revisión, se actualizan aspectos epidemiológicos, fisiopatológicos y clínico-terapéuticos y se conduce una búsqueda sistemática de casos de AF reportados en Latinoamérica. La prevalencia de AF en poblaciones caucásicas es estimada entre 2 y 5 casos por 100 000 habitantes. En Latinoamérica se han publicado 35 estudios que reúnen 1481 casos en 6 países. Causada por la expansión anormal de repeticiones GAA en el gen FXN, la etiopatogenia está asociada a una reducción en los niveles de la proteína frataxina (que altera el metabolismo energético) y el acúmulo de hierro mitocondrial. El fenotipo clásico de AF suele comenzar antes de los 25 años, aunque hay otros de inicio tardío y retención de reflejos. La sintomatología se caracteriza por ataxia progresiva, alteración sensitiva, arreflexia, disartria, y alteraciones oculomotoras, además de compromiso cardiaco, endocrino y musculoesquelético. El diagnóstico requiere evaluación neurológica detallada, estudios neurofisiológicos, neuroimágenes y pruebas bioquímicas pero el enfoque determinante es el estudio genético que demuestre variantes genéticas bialélicas en el gen FXN. El manejo es multidisciplinario, orientado a aminorar los síntomas, prevenir complicaciones y brindar asesoramiento genético apropiado. Recientemente se ha aprobado el primer tratamiento farmacológico para AF con varios más en fases de experimentación.

SUMMARY Friedreich Ataxia (FA) is an autosomal recessive neurodegenerative disease with multisystemic involvement. This update of epidemiological, pathophysiological, and clinico-therapeutic aspects of FA, includes a systematic review of cases in Latin America. The estimated FA prevalence in Caucasian populations is between 2 to 5 cases per 100 000. In Latin America, 1481 cases have been published in 35 articles from six different countries. Caused by an abnormally repeated expansion of GAA trinucleotide inside the FXN gene, FA's etiopathogenesis is associated with reduced levels of the frataxin protein, which disturb the energy metabolism and result in mitochondrial iron accumulation. The classic phenotype usually shows symptoms before the age of 25, although there are others with a later onset. The main symptoms of AF are progressive ataxia, sensory disturbances, areflexia, dysarthria, and oculomotor alterations, in addition to cardiac, endocrine, and musculoskeletal compromise. Diagnostic workup requires a detailed neurological examination, neuroconduction studies, neuroimaging, and biochemical tests. The definitive diagnosis is provided by genetic testing showing biallelic variants within the FXN gene. The management is multidisciplinary, aimed at reducing symptoms, preventing complications, and providing an appropriate genetic counseling. Recently, the first pharmacological treatment for AF has been approved, with several others in clinical assessment trials.

Diabetes mellitus y ataxia de Friedreich en un niño: una difícil coexistencia / Diabetes mellitus and Friedreich´s ataxia in a child: a complicated coexistence

La ataxia de Friedreich, de herencia autosómica recesiva causada por una expansión repetida de trinucleótidos se asocia, entre otras complicaciones sistémicas, con diabetes mellitus. La aparición de torpeza motriz, con dificultad en la carrera y el salto en un varón de 6 años motivaron el estudio genético para ataxia de Friedrich y permitieron confirmar el diagnóstico. Tres años más tarde, se diagnosticó diabetes mellitus y se inició el tratamiento con insulina. Durante el seguimiento, presentó un importante deterioro neurológico, con necesidad de usar silla de ruedas, lo que dificultó un adecuado control metabólico. Se presenta el manejo y la evolución de un paciente con ataxia de Friedreich y diabetes mellitus

Friedreich's ataxia is an autosomal recessive disease caused by trinucleotide repeat expansion, presenting among other systemic complications, diabetes mellitus. The appearance of motor clumsiness, with running and jumping difficulties in a 6-year-old boy prompted the genetic study of Friedreich's ataxia, confirming his diagnosis. After diagnosis,it was evaluated by Pediatric Cardiology, detecting the presence of non-obstructive hypertrophic cardiomyopathy, and by Pediatric Endocrinology, due to overweight. At 9 years of age, he was diagnosed with diabetes mellitus, a regimen of insulin treatment was initiated. During follow-up, he presented significant neurological deterioration, reaching the use of a wheelchair,which hinders adequate metabolic control. This is a report of a pediatric patient with Friedrich ataxia and diabetes mellitus.

Proposta de aplicação da comunicação alternativa para paciente com doença neurodegenerativa e seu impacto na qualidade vida: relato de caso / Proposal of application of alternative communication for patient with neurodegenerative disease and its impact on quality of life: case report / Propuesta de aplicación de comunicación alternativa para paciente com enfermedad neurodegenerativa y su impacto en la calidad de vida: caso clínico

Trata-se de um relato de caso de um indivíduo do sexo masculino com 51 anos, nível superior completo, nível socioeconômico favorável, diagnosticado em 1999 com Ataxia de Friedreich. Chega ao ambulatório de Fonoaudiologia, com ênfase no atendimento de adultos com doenças degenerativas, sob encaminhamento da equipe de genética do serviço do mesmo hospital. Ao exame fonoaudiológico diagnostica-se uma disfagia orofaríngea de moderada a grave e uma disartria grave. A disfagia é reabilitada via home care particular por opção do paciente, e no ambulatório, com objetivo de melhora da qualidade de vida criou-se uma proposta de aplicação da comunicação aumentativa e/ou alternativa para o desenvolvimento das habilidades de comunicação do paciente que já não estava mais se expressando. Foram realizadas duas avaliações (pré e pós terapia) e quatro sessões de intervenção terapêutica para o aprendizado e implementação da prancha de comunicação alternativa. Ao término do processo terapêutico verificou-se baixa adesão ao uso da comunicação aumentativa e/ou alternativa, mesmo com a auto-percepção da ininteligibilidade da sua fala, utilizando a pasta restrita ao atendimento fonoaudiológico. Tanto o paciente quanto seus acompanhantes referiram que mesmo após várias tentativas houve negação ao uso da comunicação alternativa. Embora tenham sido poucas sessões, não houve impacto da qualidade de vida do paciente após uso da comunicação aumentativa e/ou alternativa.

Este es un informe del caso de un hombre de 51 años, con educación universitaria completa, estatus socioeconómico favorable, diagnosticado en 1999 con ataxia de Friedreich. Llega a la clínica de terapia del habla, con énfasis en ayudar a adultos con enfermedades degenerativas, bajo la guía del equipo de genética al servicio del mismo hospital. El examen notas la disfagia orofaríngea moderada a severa y la disartria severa. La disfagia se rehabilita mediante atención domiciliaria privada a elección del paciente y en la clínica ambulatoria con el objetivo de mejorar la calidad de vida, se creó una propuesta para la aplicación de comunicación aumentativa y/o alternativa para desarrollar las habilidades de comunicación del paciente que ya no era más expresándose a sí mismos. Se realizaron dos evaluaciones (pre y post terapia) y cuatro sesiones de intervención terapéutica para aprender e implementar el tablero de comunicación alternativo. Al final del proceso terapéutico, hubo una baja adherencia al uso de comunicación aumentativa y/o alternativa, incluso con la autopercepción de la ininteligibilidad de su discurso, usando la carpeta restringida a la terapia del habla. Tanto el paciente como sus compañeros informaron que incluso después de varios intentos hubo una negación del uso de comunicación alternativa. Aunque hubo pocas sesiones, no hubo impacto en la calidad de vida del paciente después de usar comunicación aumentativa y/o alternativa.

This is a case report of a 51-year-old male, with complete college education, favorable socioeconomic status, diagnosed in 1999 with Friedreich's Ataxia. He arrives at the speech therapy clinic, with an emphasis on assisting adults with degenerative diseases, under the guidance of the genetics team at the service of the same hospital. Speech examination examines moderate to severe oropharyngeal dysphagia and severe dysarthria. Dysphagia is rehabilitated via private home care at the patient's option and in the outpatient clinic with the objective of improving quality of life, a proposal for the application of augmentative and/or alternative communication was created to develop the communication skills of the patient who was no longer expressing himself. Two evaluations (pre and post therapy) and four therapeutic intervention sessions were carried out to learn and implement the alternative communication board. At the end of the therapeutic process, there was low adherence to the use of augmentative and / or alternative communication, even with the self-perception of the unintelligibility of his speech, using the folder restricted to speech therapy. Both the patient and his companions reported that even after several attempts there was a denial of the use of alternative communication. Although there were few sessions, there was no impact on the patient's quality of life after using augmentative and/or alternative communication.

Cardiomyopathy as the first manifestation of Friedreichs ataxia

We present the case of a female patient diagnosed in childhood with Friedreich Ataxia (FA). At the age of 6, she developed left congestive heart failure with cardiomyopathy, as evident on echocardiogram. Neurologic signs only appeared at age 7, including marked loss of muscle mass, gait instability, muscle clonus, and Babinski's signal. At age 27, she had a stroke and was hospitalized; a few days later, she had a cardiorespiratory arrest with asystole, leading to death. The autopsy disclosed severe cardiomyopathy and significant myocardial replacement with fibrosis; therefore, the cause of death was assumed to be heart failure. Compared to the literature, our case has some unique features, such as cardiac disease as the presenting manifestation instead of gait instability, which is the major initial sign in most FA cases. Since our patient was submitted to an autopsy, it was an opportunity to retrieve important data to confirm the diagnosis and to evaluate the pathophysiology of this entity, such as myocardium fibrosis and cerebellar degeneration. In summary, our case demonstrates that cardiac disease can be the first manifestation of FA, with eventual diagnostic and prognostic implications. In addition, the autopsy provided findings of severe cardiomyopathy associated with FA.

The importance of central auditory evaluation in Friedreich's ataxia / A importância da avaliação auditiva central na ataxia de Friedreich

ABSTRACT Objective To assess central auditory function in Friedreich's ataxia. Methods A cross-sectional, retrospective study was carried out. Thirty patients underwent the anamnesis, otorhinolaryngology examination, pure tone audiometry, acoustic immittance measures and brainstem auditory evoked potential (BAEP) assessments. Results The observed alterations were: 43.3% in the pure tone audiometry, bilateral in 36.7%; 56.6% in the BAEP test, bilateral in 50%; and 46.6% in the acoustic immittance test. There was a significant difference (p < 0.05) in the comparison between the tests performed. Conclusion In the audiological screening, there was a prevalence of the descending audiometric configuration at the frequency of 4kHz, and absence of the acoustic reflex at the same frequency. In the BAEP test, there was a prevalence of an increase of the latencies in waves I, III and V, and in the intervals of interpeaks I-III, I-V and III-V. In 13.3% of the patients, wave V was absent, and all waves were absent in 3.3% of patients.

RESUMO Objetivo Avaliar a função auditiva central na ataxia de Friedreich (AFRD). Métodos Foi realizado um estudo retrospectivo de corte transversal. 30 pacientes realizaram anamnese, avaliações otorrinolaringológica, audiológica, imitanciométrica e do potencial evocado auditivo de tronco encefálico (PEATE). Resultados As alterações observadas foram: 43,3% no exame audiométrico sendo 36,7% dos casos, bilateralmente; 56,6% na avaliação do PEATE com 50% dos casos, bilateralmente e 46,6% no exame imitanciométrico. Houve diferença significativa (p < 0,05) na comparação entre os exames realizados. Conclusão No exame audiológico, ocorreu uma preponderância maior da configuração audiométrica descendente a partir da freqüência de 4kHz e ausência do reflexo acústico na mesma frequência. No exame do PEATE, houve prevalência do aumento das latências nas ondas I, III e V, e nos intervalos dos interpicos I-III, I-V e III-V. Em 13,3% dos casos, a onda V estava ausente, e em 3,3% dos casos, todas as ondas estavam ausentes.

Friedreich's Ataxia: dance and somatic education a case report

This research aims to determine the effects of a dance program in dialogue with somatic education in psychomotor aspects in a subject with Friedreich ataxia. We used the research method intra-subject BAB design, were phase "B" comprises the treatment phase through interventions with stimuli, and "A" the stimuli are removed. We performed a dance program with 24 interventions on a subject with Friedreich Ataxia, and assessed pre- and post-program through the Monitoring Instrument Learning in Educational Dance. The results showed that the dance program with somatic education can improve the analyzed skills: getting up, sitting, shifting feet, shifting the ground, sitting position, body image, movement rhythm, and fluency movement.(AU)

Otoneurological Abnormalities in Patients with Friedreich's Ataxia

Abstract Introduction Friedreich's ataxia is a neurodegenerative disease and progressive by nature. It has autosomal recessive inheritance and early onset inmost cases. Nystagmus and hearing loss (in some cases) make up some of the common symptoms seen in this disorder. Objective The objective of this study is to examine vestibular disorders in patientswith Friedreich ataxia. Methods We conducted a retrospective cross-sectional study. We evaluated 30 patients with ages ranging from six to 72 years (mean age of 38.6 ( 14.7). The patients underwent the following procedures: anamnesis, ENT, and vestibular evaluations. Results Clinically, the patients commonly had symptoms of incoordination of movement (66.7%), gait disturbances (56.7%), and dizziness (50%). In vestibular testing, alterations were predominantly evident under caloric testing (73.4%), gaze nystagmus testing (50.1%), rotational chair testing (36.7%), and optokinetic nystagmus testing (33.4%). The presence of alterations occurred under examination in 90% of subjects, with the majority occurring in those with central vestibular dysfunction (70% of the examinations). Conclusion The most evident neurotological symptoms were incoordination of movement, gait disturbances, and dizziness. Alterations in vestibular examinations occurred in 90% of patients, mostly in the caloric test, with a predominance of deficient central vestibular system dysfunction.

Urinary Symptoms and Urodynamics Findings in Patients with Friedreich's Ataxia

Purpose To assess the prevalence of LUTS, urinary tract and urodynamics changes in patients with Friedreich's Ataxia (FA), the most common form of hereditary ataxia. Materials and Methods This study evaluated 258 patients with genetically confirmed diagnoses of FA. Of the patients, 158 responded to a questionnaire which assessed their urinary symptoms. Patients with clinical changes underwent renal function examinations, ultrasound, and urodynamic studies (UDS). Results The sample analyzed showed that 82% of the patients complained of LUTS, although only 22% related the symptoms with quality of life impairment. Twenty eight (18%) of them agreed to undergo urodynamic evaluation. Urgency was the most common symptom. The exam was normal in 4 (14%) and detrusor underactivity was the most common finding. 14% (4 patients) presented with dilatation of the upper urinary tract at ultrasound scans. None of them had creatinine alterations. Conclusions LUTS was found in a large percentage of patients with FA, but only a few related it to their quality of life impairment. Although creatinine levels was normal in this sample, some patients may show upper urinary tract abnormalities, with deserves close observation and proper care. .

Ataxia de Friedreich de inicio tardío: Descripción clínica en una familia argentina / Late onset Friedreich ataxia: clinical description of a family in Argentina

La ataxia de Friedreich (AF) es la ataxia hereditaria más común; está causada por una expansión anormal del triplete GAA del primer intrón del gen X25 en el cromosoma 9. Se presenta comúnmente en menores de 25 años y se asocia a trastornos musculoesqueléticos, endocrinos y miocárdicos. Entre sus variantes fenotípicas se describen casos que inician su sintomatología después de los 25 años de edad, definidos como ataxia de Freidreich de inicio tardío (AFIT). Nuestro objetivo fue la descripción de una familia con tres hermanos afectados, todos de inicio tardío. Los síntomas se iniciaron entre los 32 y 34 años, con trastornos de la marcha y disartria cerebelosa, que se agravaron en el curso de 6 a 12 meses, haciéndose más evidentes. Ninguno presentaba compromiso musculoesquelético ni miocárdico. No existían antecedentes familiares de ataxias u otros trastornos neurológicos. En 2 casos se realizó estudio genético que evidenció la expansión anormal del triplete GAA, confirmando el diagnóstico de AF. Se realizaron resonancias magnéticas (RM) de encéfalo, encontrándose atrofia medular con preservación de estructuras cerebelosas en dos casos, y atrofia vermiana y medular en el tercero. En las ataxias cerebelosas con disartria y pérdida de la sensibilidad profunda que se inician después de los 25 años, sean éstas esporádicas o vinculadas a una herencia recesiva, se debe considerar la investigación de expansiones GAA en el gen de la AF.

Friedreich Ataxia (FA) is the most common hereditary ataxia, caused by abnormal expansion of the GAA triplet of the first intron of the X25 gene on chromosome 9. Clinically it occurs in patients under the age of 25 and it is frequently associated with musculoskeletal, endocrine and myocardial disorders. Among their phenotypic variants there are patients starting their symptoms after the age of 25. The latter group is defined as late onset Freidreich ataxia (LOFA). The objective of this work is to present three siblings affected by late onset Friedreich ataxia. Their symptoms began between the ages of 32 and 34, with gait disturbance and dysarthria of cerebellar type, which worsened, thus becoming more evident in the course of 6-12 months. None had musculoskeletal or myocardial involvement. There was no family history of ataxia or other neurological disorders. Two of these patients underwent genetic study that showed abnormal expansion of GAA triplet confirming the diagnosis of FA. A magnetic resonance imaging (MRI) of the brain was performed. Proximal spinal cord atrophy, sparing cerebellar structures, was found in two of the cases and vermian atrophy associated with proximal spinal cord atrophy was observed in the third one. Molecular testing GAA expansions in the FA gene should be considered in cerebellar ataxia with dysarthria and loss of proprioception.

Avances en el tratamiento de las ataxias crónicas / [Therapeutic developments in chronic ataxias].

Autosomal recessive cerebellar ataxias belong to a broader group of disorders known as inherited ataxias. In most cases onset occurs before the age of 20. These neurological disorders are characterized by degeneration or abnormal development of the cerebellum and spinal cord. Currently, specific treatment is only available for some of the chronic ataxias, more specifically those related to a known metabolic defect, such as abetalipoproteinemia, ataxia with vitamin E deficiency, and cerebrotendinous xanthomatosis. Treatment based on a diet with reduced intake of fat, supplementation of oral vitamins E and A, and the administration of chenodeoxycholic acid could modify the course of the disease. Although for most of autosomal recessive ataxias there is no definitive treatment, iron chelators and antioxidants have been proposed to reduce the mitochondrial iron overload in Friederich’s ataxia patients. Corticosteroids have been used to reduce ataxia symptoms in ataxia telangiectasia. Coenzyme Q10 deficiency associated with ataxia may be responsive to Co Q10 or ubidecarenone supplementations. Early treatment of these disorders may be associated with a better drug response.

[cartas] / [Letters]

Floridablanca, Santander, septiembre 19 de 2012 Señor Editor: Los doctores Silva, Prada, Páez y colaboradores, en la edición de la Rev Colomb Cardiol 2012; 19 (2): 100-104, presentaron el caso de un paciente con Ataxia de Friedreich (AF), en el que hicieron una interesante discusión sobre el compromiso cardíaco y neurológico, y algunas consideraciones acerca del trasplante cardíaco en estos pacientes (1). Como lo mencionan los autores, la ataxia de Friedreich es un trastorno degenerativo cerebeloso con un patrón de herencia autosómico recesivo, en el cual el compromiso cardiaco representa una de las principales causas de muerte, y en la que se ha encontrado disfunción mitocondrial y no es de carácter infiltrativo como se menciona; esto explica la fisiopatología de otras manifestaciones en estos pacientes como la misma diabetes. La cardiopatía hace parte del espectro clínico tardío y cuando se diagnostica, la discapacidad neurológica instaurada usualmente es severa y el pronóstico global muy comprometido. Recientemente, nuestro grupo publicó el caso de un paciente con historia de insuficiencia cardiaca diagnosticada desde los 18 años, que requirió trasplante cardiaco cuatro años después de iniciados los síntomas. Inicialmente se consideró que el origen de la cardiopatía era idiopático; sin embargo, seis meses después del trasplante, el paciente presentó alteraciones del equilibrio, la marcha y el lenguaje, lo que sugirió el diagnóstico de ataxia de Friedreich, el cual fue confirmado tras la determinación de la mutación homocigota con expresión de 900 y 700 tripletas GAA (2). Al re-interrogar al paciente, manifestó síntomas sutiles desde los 15 años, dados especialmente por sensación de debilidad en miembros inferiores que le generaba una ligera alteración de su patrón de marcha usual. Todos estos síntomas solo fueron evidentes pocos meses después del trasplante. De acuerdo con nuestro conocimiento, el caso reportado por nuestro grupo es el tercer caso publicado de trasplante cardiaco en un paciente con esta condición neurológica. Las dos publicaciones previas hipotetizaban un efecto del trasplante cardiaco sobre la condición neurológica de estos pacientes debido a una aparente mejoría en la ataxia y la disartria en los meses posteriores al trasplante. No obstante, los periodos de seguimiento de estos casos eran cortos (menores a dos años). A la fecha, nuestro paciente ha sido seguido durante nueve años, tiempo durante el cual ha mantenido una excelente función cardiaca, pero también una clara progresión de su compromiso neurológico a causa de la cual en el momento requiere asistencia para la marcha. A pesar del compromiso neurológico, el paciente ha llevado una calidad de vida aceptable, con posibilidades de realizar múltiples actividades cotidianas y de incorporarse activamente con su familia.

Cardiopatía dilatada en ataxia de Friedreich: el punto sin retorno / Dilated cardiomyopathy in Friedreich's ataxia: point of no return

Las cardiopatías infiltrativas se caracterizan por el depósito de sustancias en el miocardio que causan un impacto negativo en la arquitectura de la pared ventricular. La ataxia espino-cerebelosa de Friedreich es una enfermedad degenerativa, heredada, con carácter autosómico recesivo. Clínicamente se caracteriza por ataxia de extremidades y tronco, hiporreflexia, neuropatía periférica, retinopatía y cardiopatía, entre otros. La afectación cardíaca es muy frecuente y se detectan alteraciones en estudios pos-mortem en 95% a 100% de los pacientes. La tasa de mortalidad es elevada y se considera una enfermedad incurable, a pesar de la existencia actual de múltiples medicamentos en estudio basados en los fundamentos fisiopatológicos de esta afección.

Infiltrative heart diseases are characterized by deposit of substances in the myocardium that cause a negative impact on the architecture of the ventricular wall. Friedreich's spino-cerebellar ataxia is a degenerative disease, inherited in an autosomal recessive pattern. Clinically it is characterized by limb and trunk ataxia, hyporeflexia, peripheral neuropathy, retinopathy and heart disease among others. Cardiac involvement is common and on post-mortem studies cardiac abnormalities are found in 95% to 100% of patients. The mortality rate is high and it is considered an incurable disease, despite the current existence of multiple medications being studied, based on the pathophysiological basis of this condition.

Ataxia de friedreich: relato de um caso com manifestação tardia / Friedreich?s ataxia: a case report with late manifestation

A Ataxia de Friedreich é uma doença neurodegenerativa progressiva, de herança autossômica recessiva, que foi descrita pela primeira vez por Nicholaus Friedreich, em 1863. A mutação responsável por essa doença se encontra no cromossomo nove, onde ocorre uma expansão de trinucleotídios GAA. O gene afetado tem a função de codificar a proteína mitocondrial frataxina, que está envolvida no metabolismo do ferro. O principal sintoma é a ataxia (coordenação prejudicada), que, no início, é mais evidente nos membros inferiores e, posteriormente, atinge os membros superiores. Este estudo teve por objetivo relatar um caso de Ataxia de Friedreich, uma doença genética rara de caráter degenerativo que, ao contrário do prognóstico esperado, se manifestou mais tardiamente no indivíduo afetado. Este trabalho também descreve a evolução clínica, enfocando os sintomas e deficiências que o paciente apresentou antes e após o diagnóstico, bem como, discute as bases moleculares que podem ter contribuído para a manifestação tardia da doença, além dos tratamentos emergentes.

The Friedreich?s ataxia is a progressive neurodegenerative disease with autosomal recessive inheritance, which was first described by Nicholaus Friedreich in 1863. The mutation responsible for this disease is located on chromosome nine, where there is a GAA trinucleotide expansion repeats. The affected gene function is to encode the mitochondrial protein frataxin, which is involved in the iron metabolism. The main symptom is ataxia (impaired coordination), which at first is more evident in the lower limbs and eventually reaches the upper limbs. This study aimed to report a case of Friedreich?s Ataxia, a rare genetic disease with degenerative characteristic that manifested itself later in the affected individual unlike the expected outcome. This paper also describes the clinical course, focusing on the symptoms and disabilities that the patient presented before and after diagnosis, and also discusses the molecular basis that may have contributed to the late-onset of the disease besides the emerging treatments.

Fenotipo y genotipo de once pacientes con Ataxia de Friedreich / Friedreic's Ataxia: Phenotype and Genotype in Eleven Patients

Introducción: La ataxia de Friedreich (FRDA) es una enfermedad autosómica recesiva debida a una mutación en el gen X25. Dicho gen está localizado en el cromosoma 9 y codifica para la proteína frataxina. La enfermedad es causada por la repetición del trinucleótido GAA. En individuos normales la secuencia GAA se encuentra repetida entre siete y veintidós veces, mientras que, en pacientes con ataxia de Friedreich GAA puede estar repetida cientos o miles de veces. Objetivos: Evaluar si existe correlación entre el tamaño de la expansión, la edad de inicio de FRDA y su severidad en la muestra seleccionada. Métodos: - Se estudiaron once pacientes con fenotipo típico de ataxia de Friedreich. El análisis molecular por PCR determinó la expansión del trinucleótido GAA. Se analizó la correlación entre la edad de inicio de FRDA y su progresión con el número de repeticiones GAA. Resultados y conclusiones: - El análisis molecular por PCR mostró ocho pacientes homocigotos para la expansión, y tres negativos. El promedio del tamaño de las expansiones en los alelos es 622±5 con un promedio correspondiente de la edad inicio de FRDA 13±8. Para el tamaño de la muestra no se observó una correlación estadística significativa entre la edad de inicio de la enfermedad y el número de repeticiones, pero sí una tendencia a correlacionarse de forma inversa (p<0.11). El diagnóstico molecular de FRDA sumado a la comprensión de su fisiología y a la utilización de los criterios de inclusión de Harding, constituye un paso importante en el logro de un tratamiento óptimo de la enfermedad.

Introduction: - Friedreich's ataxia is an autosomal recessive disease due to a mutation in gene X25. This gene codes for frataxin and it is located on chromosome 9. The disease is caused by a triplet particular sequence of bases (GAA). Normally, the GAA sequence is repeated 7 to 22 times, but in people with Friedreich's ataxia, it can be repeated hundreds or even over thousand times. Objectives: To determine if there is a correlation between clinical and molecular findings in our FRDA patients. Methods: Eleven patients with the typical Friedreich´s ataxia phenotype were studied by PCR we determined the size of the GAA expansions, and analyzed the correlation of age at onset and rate of disease progression with the number of GAA repetitions. Results and conclusions: Molecular analysis by PCR showed eight homozygous patients for the expansion and three negative. The average of the size of the expansions in the allele was of 622±5 with an average in the age of beginning of 13±8. For the sample size, there was no significant statistical correlation between the age of beginning of the disease and the number of repetitions, although there was like an inverse correlation. Besides understanding of FRDA physiology and the Harding clinical inclusion criteria, molecular diagnosis is an important step in the achievement of an optimal therapeutic treatment.

Análisis molecular de la ataxia de Friedreich en Colombia / Molecular analysis of the ataxia of Friedreich in Colombia

Introducción: la ataxia de Friedreich (FRDA), enfermedad autosómica recesiva, está asociada a una expansión de trinucleótidos GAA en el primer intrón del gen X25. La severidad de la enfermedad se asocia al número de repeticiones. Objetivos: evaluar si existe correlación clínica y molecular en nuestros pacientes con FRDA. Material y métodos: se estudiaron 24 pacientes con FRDA y 50 sujetos normales. Evaluamos la severidad de la enfermedad utilizando la escala internacional cooperativa de ataxia (EICA). Se tomaron muestras de sangre en pacientes y controles y mediante técnica de PCR se determinó el número de repeticiones GAA del gen FRDA. Resultados: documentamos consanguinidad en cinco familias y herencia autosómica recesiva en siete. En 17 pacientes se observó la forma típica de FRDA y en siete la variante con reflejos conservados (FARR). La edad de inicio osciló entre los tres y 22 años. Las repeticiones GAA en la población colombiana presentaron un rango de 1-26. Un paciente heterocigoto para la expansión se consideró portador de una mutación en el otro alelo. Veinte pacientes fueron homocigotos para la expansión GAA, con repeticiones en un rango de 206 a 951. El promedio en el menor y el mayor alelo fue 650 y 709 repeticiones GAA respectivamente. La expansión es inestable durante la transmisión, observándose variabilidad en el número de repeticiones GAA en los descendientes. Encontramos una relación inversa entre el tamaño de las expansiones y la edad de inicio de la enfermedad (p<0.05) y una relación directa entre la expansión y la severidad de la enfermedad (p<0.0.1). El estudio del polimorfismo FAD1 en los pacientes indicó una fuerte asociación del alelo B con el cromosoma de FRDA. Conclusiones: el espectro de la expansión en FRDA es amplio en la población colombiana. Puede existir un efecto fundador de la mutación asociándose al alelo FAD1_B o bien las mutaciones de FRDA se originan en un alelo de riesgo. El diagnóstico molecular a través de la determinación de la expansión GAA es una herramienta esencial en la práctica clínica y en la consejería genética en pacientes con ataxia recesiva o esporádica

Ataxia de Friedreich. Avaliação cardiáca de 24 pacientes com diagnóstico clínico e revisão da literatura / Friedreich's ataxia. Cardiac evaluation of 25 patients with clinical diagnosis and literature review

OBJECTIVE - Cardiac evaluation (clinical, electrocardiographic and echocardiographic) of 25 Brazilian patients with clinical diagnosis of Friedreich's ataxia (FA) related to the frequency and the size of GAA repeats (unstable expansion of trinucleotide repeats that results in the disease). METHODS - Clinical and cardiac study including electrocardiogram and echocardiogram of all patients and molecular analysis to detect the frequency and the size of GAA expansion, by polymerase chain reaction analysis. RESULTS - Homozygous GAA expansion was detected in 17 patients (68 percent) -- all typical cases. In 8 (32 percent) cases (6 atypical and 2 typical), no GAA expansion was observed, therefore it was not considered Friedreich's ataxia. All patients with GAA expansion (100 percent) had electrocardiographic abnormalities, and only 25 percent of the cases without GAA expansion had some abnormality on this exam. However, only 6 percent of all patients revealed some signals/symptoms suggestive of cardiac involvement. CONCLUSION - A molecular analysis is essential to confirm the diagnosis of Friedreich's ataxia; however, an adequate cardiac evaluation, including an electrocardiogram, was extremely useful to better screening the patients which should perform these molecular analysis

Friedreich's ataxia: clinical and molecular study of 25 Brazilian cases

INTRODUCTION: Friedreich's ataxia is a neurodegenerative disorder whose clinical diagnostic criteria for typical cases basically include: a) early age of onset (< 20 or 25 years), b) autosomal recessive inheritance, c) progressive ataxia of limbs and gait, and d) absence of lower limb tendon reflexes. METHODS: We studied the frequency and the size of expanded GAA and their influence on neurologic findings, age at onset, and disease progression in 25 Brazilian patients with clinical diagnosis of Friedreich's ataxia - 19 typical and 6 atypical - using a long-range PCR test. RESULTS: Abnormalities in cerebellar signs, in electrocardiography, and pes cavus occurred more frequently in typical cases; however, plantar response and speech were more frequently normal in this group when the both typical and atypical cases were compared. Homozygous GAA expansion repeats were detected in 17 cases (68 percent) - all typical cases. In 8 patients (32 percent) (6 atypical and 2 typical), no expansion was observed, ruling out the diagnosis of Friedreich's ataxia. In cases with GAA expansions, foot deformity, cardiac abnormalities, and some neurologic findings occurred more frequently; however, abnormalities in cranial nerves and in tomographic findings were detected less frequently than in patients without GAA expansions. DISCUSSION: Molecular analysis was imperative for the diagnosis of Friedreich's ataxia, not only for typical cases but also for atypical ones. There was no genotype-phenotype correlation. Diagnosis based only on clinical findings is limited; however, it aids in better screening for suspected cases that should be tested. Evaluation for vitamin E deficiency is recommended, especially in cases without GAA expansion

Ataxia de Friedreich y embarazo / Friedreich's ataxia and pregnancy

Se presenta un caso clínico exitoso de embarazo y parto en un paciente portadora de una ataxia de Friedrich

Clinical and molecular studies in five Brazilian cases of Friedreich ataxia

Friedreich ataxia (FRDA), the most commom autosomal recessive ataxia, is caused in 94 per cent 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.