Terapia genética de injeção intravítrea de rAAV2-ND4 para neuropatia óptica hereditária de Leber: uma revisão sistemática / rAAV2-ND4 intravitreal injection gene therapy for Leber's hereditary optic neuropathy: a systematic review

RESUMO A neuropatia óptica hereditária de Leber é uma doença mitocondrial hereditária neurodegenerativa. A taxa potencial de recuperação espontânea é controversa na literatura. A terapia genética tem sido estudada como suporte aos pacientes. O objetivo desta revisão foi avaliar qualitativamente a segurança, os efeitos adversos e a eficácia da terapia gênica disponível. Trata-se de uma revisão sistemática de artigos indexados nas bases de dados PubMed®, Biblioteca Virtual em Saúde, SciELO, Cochrane, ScienceDirect, Scopus e Lilacs no primeiro semestre de 2021. Os critérios de inclusão e filtros foram: artigos relacionados ao tema, estudos randomizados, ensaios clínicos, trabalhos em humanos, últimos 5 anos, nas línguas portuguesa, inglesa e espanhola e texto completo disponível gratuitamente. Os parâmetros de exclusão foram: artigos duplicados, fuga ao tema, artigos de revisão, trabalhos não disponíveis e que fugiam aos critérios de inclusão. O coeficiente de kappa foi 0,812. A terapia não apresentou efeitos adversos sérios em nenhum dos artigos selecionados, e os efeitos menores sofreram 100% de remissão espontânea após o tratamento. Apesar de NAbs terem sido encontrados no soro de alguns pacientes, não houve associação entre a resposta imune adaptativa e a injeção do vetor viral. O tratamento foi eficaz na melhora da acuidade e campo visual. Vários estudos confirmaram a eficácia da terapia gênica, em doses baixas e médias, na melhora da acuidade visual e também sobre os efeitos adversos comuns relacionados à altas doses. A resposta imune humoral e a variação dos NAbs no soro foi citada em mais de um artigo. A terapia foi eficaz na melhora da acuidade visual e os efeitos adversos que surgiram foram tratados facilmente. No entanto, a resposta imune humoral ainda precisa ser estudada.

ABSTRACT Leber's Hereditary Optic Neuropathy (LHON) is an inherited neurodegenerative mitochondrial disease. The potential rate of spontaneous recovery is controversial in the literature. Gene therapy has been studied to support patients. The objective of this review was to qualitatively assess the safety, adverse effects, and efficacy of available gene therapy. This is a systematic review of articles indexed in PubMed®, VHL, SciELO, Cochrane, ScienceDirect, Scopus, and Lilacs databases, in the first half of 2021. Inclusion criteria and filters were: articles related to the topic, randomized studies, clinical trials, work in humans, last 5 years, in Portuguese, English, and Spanish and full text available for free. The exclusion parameters were: duplicate articles, not related to the topic, review articles, not available works, and works that did not meet the inclusion criteria. The kappa coefficient was 0.812. The therapy had no serious adverse effects in any of the selected articles, and minor effects experienced 100% spontaneous remission after treatment. Although NAbs were found in the serum of some patients, there was no association between the adaptive immune response and the injection of the viral vector. The treatment was effective in improving acuity and visual field. Several studies have confirmed the effectiveness of gene therapy, at low and medium doses, in improving visual acuity and also on common adverse effects related to high doses. The humoral immune response and the variation in serum NAbs was cited in more than one article. The therapy was effective in improving visual acuity and the adverse effects that arose were easily treated. However, the humoral immune response still needs to be studied.

A Review of Mitochondrial Optic Neuropathies: From Inherited to Acquired Forms.

In recent years, the term mitochondrial optic neuropathy (MON) has increasingly been used within the literature to describe a group of optic neuropathies that exhibit mitochondrial dysfunction in retinal ganglion cells (RGCs). Interestingly, MONs include genetic aetiologies, such as Leber hereditary optic neuropathy (LHON) and dominant optic atrophy (DOA), as well as acquired aetiologies resulting from drugs, nutritional deficiencies, and mixed aetiologies. Regardless of an inherited or acquired cause, patients exhibit the same clinical manifestations with selective loss of the RGCs due to mitochondrial dysfunction. Various novel therapies are being explored to reverse or limit damage to the RGCs. Here we review the pathophysiology, clinical manifestations, differential diagnosis, current treatment, and promising therapeutic targets of MON.

[Leber hereditary optic neuropathy: Usefulness of next generation sequencing to study mitochondrial mutations on apparent homoplasmy]. / Neuropatía óptica de Leber: utilidad de la secuenciación masiva en el estudio de mutaciones mitocondriales en aparente homoplasmia.

BACKGROUND AND OBJECTIVE: Leber hereditary optic neuropathy is characterized by acute and subacute visual loss, produced by mitochondrial DNA mutations. PATIENTS AND METHODS: The molecular study of a family with only one affected member is presented. RESULTS: In the index case and in her mother, the mitochondrial mutation m.11778G>A in the MT-ND4 was detected in the heteroplasmic state. The index case's sister, without ocular manifestations, asked for genetic counseling. The study of the mentioned mutation by Sanger sequencing identified it in an apparent homoplasmic state. However, by means of next-generation sequencing (NGS), the mutation was actually in a heteroplasmic state. CONCLUSIONS: Regarding genetic counseling, verifying a mutation in homoplasmic state is really important. We have observed that NGS allows us to discriminate between high levels of heteroplasmy and homoplasmy, meaning that it is a useful technique for the analysis of apparent homoplasmic results obtained with less sensitive technique, as Sanger sequencing.

Neuropatía óptica hereditaria de Leber: reporte de caso / Leber’s hereditary optic neuropathy: a case report

Las enfermedades mitocondriales pueden afectar de manera sistémica u orgánica a los pacientes. Un tipo de afección es la neuropatía óptica hereditaria de Leber, que causa una atrofia del nervio óptico y produce una disminución del campo visual y de la agudeza visual. En ocasiones, esta enfermedad no presenta hallazgos significativos en el fondo de ojo y es necesario que se le haga una exploración lo más completa posible para encontrar el problema. En este artículo se presenta el manejo que se le dio al paciente, desde el diagnóstico probable hasta que se llegó a corroborar, y lo más actual acerca de esta enfermedad.

Mitochondrial diseases can affect patients in a systematic or organic way. A type of condition is Leber’s hereditary optic neuropathy, which causes atrophy of the optic nerve and causes a reduction of the visual field and visual acuity. On occasion, this disease does not show significant findings in the fundus and it is necessary to further explore it as completely as possible in order to find the problem. In this paper we will find the way in which the patient was handled from the time of the probable diagnosis until its corroboration and the latest information about the disease.

Neuromyelitis optica antibody in Leber hereditary optic neuropathy: case report / Anticorpo da neuromielite óptica em neuropatia óptica hereditária de Leber: relato de caso

Neuromyelitis optica antibody (or aquaporin-4 antibody) is a well stablished serum marker associated to high-risk neuromyelitis optica syndrome that presents as an inflammatory demyelinating disease characterized by the occurrence of bilateral and simultaneous optic neuritis without complete visual recovery or it occurs as an isolated episode of transverse myelitis accompanied by longitudinally extensive spinal cord lesions. On the other hand, Leber hereditary optic neuropathy is a primarily hereditary disorder that affects all tissues of the body and its clinical presentation is tissue-specific for the optic nerve and, eventually, it might reach the spinal cord. Overlapping clinical features of neuromyelitis optica and Leber hereditary optic neuropathy may suggest common target organ diseases. The case report described herein emphasizes the coexistence of serum markers of both diseases, and suggests that further investigation of this challenging clinical presentation is warranted to confirm or rule out this association.

Anticorpo da neuromielite óptica (ou anticorpo aquaporina-4) é um marcador sorológico bem estabelecido associado à síndrome de alto risco para neuromielite óptica, doença inflamatória desmielinizante, caracterizada por ocorrência bilateral, simultânea de neurite óptica ou por episódio isolado de mielite transversa com achado de lesões espinais longitudinais extensas. Por outro lado, a neuropatia óptica hereditária de Leber é uma doença primariamente hereditária que afeta todos os tecidos do corpo e sua apresentação clínica envolve o nervo óptico e, eventualmente, a medula espinal. Aspectos clínicos comuns sugerem que neuromielite óptica e neuropatia óptica hereditária de Leber possam atingir os mesmos órgãos. O caso descrito enfatiza a coexistência de marcadores sorológicos das duas doenças e sugere a necessidade de investigação futura desta apresentação clínica atípica para confirmar ou não esta associação.

Neuropatía óptica hereditaria de Leber / Leber´s hereditary optic neuropathy

La neuropatía óptica hereditaria de Leber es una enfermedad de herencia materna que se caracteriza por la pérdida subaguda, indolora y bilateral, aunque por lo general no siempre al unísono de la visión central. Predomina en hombres jóvenes y es causada por mutaciones puntuales del ADN mitocondrial. Esta es una de las neuropatías ópticas hereditarias más frecuentes y altamente invalidante, cuyo diagnóstico de certeza lo constituyen los estudios moleculares. El propósito de esta revisión es alertar en cuanto a su diagnóstico y posible incremento en condiciones ambientales favorecedoras. Se realizó una búsqueda automatizada de artículos científicos relacionados con el tema, en PUBMED e Hinari, que resultó en 37 publicaciones realizadas durante los años 1988-2010. Se estudiaron y discutieron aspectos de la enfermedad tales como antecedentes históricos, factores de riesgo, epidemiología, genética, características clínicas, diagnóstico y tratamiento; además de profundizar en su estado actual en nuestro contexto. En Cuba actualmente se conoce de la existencia de varias familias que padecen la neuropatía óptica hereditaria de Leber. El alza de la incidencia probablemente se debió a las condiciones medioambientales que favorecen o son factores de riesgo de esta entidad, como ocurrió durante la pasada epidemia de neuropatía óptica en Cuba. Cada día se producen más avances en el campo de la genética, que permiten identificar un número mayor de mutaciones asociadas a esta entidad. Esto unido al conocimiento de las características clínicas de la enfermedad ha permitido identificar las familias afectadas y actuar sobre los factores de riesgo.

Leber´s hereditary optic neuropathy is a maternally inherited disease characterized by subacute, painless and bilateral loss of the central vision, although not always at the same time. It predominates in young men and is caused by mitochondrial DNA spot mutations. This is one of the most common hereditary and highly disabling optic neuropathy, the precise diagnosis of which is based on the molecular studies. The purpose of this article was to alert specialists on the possible diagnosis and increase of this impairment under favorable environmental conditions. A computerized search of scientific articles related to the subject was made in Hinari and PUBMED, which resulted in 37 publications during the years 1988 through 2010. Several disease aspects such as historical background, risk factors, epidemiology, genetics, clinical features, diagnosis and treatment were studied and discussed, in addition to delving into current status of the disease in our country. Several Cuban families are presently known to be affected by Leber´s hereditary optic neuropathy. The rise of incidence was probably due to environmental conditions that favor or are risk factors for this entity, as occurred during the last epidemic of optic neuropathy in Cuba. Every day there are more advances in the field of genetics that allows identifying a higher number of mutations associated with this disease. This event together with advanced knowledge of its clinical features has made it possible to identify the affected families and to control the risk factors.

Error diagnóstico en la neuropatía óptica epidémica / Diagnostic error in epidemic optic neuropathy

La forma óptica de la epidemia de neuropatía, aparecida en el decenio pasado en Cuba, ha sido motivo de discusión por el posible hiperdiagnóstico, de los más de 22 000 casos notificados. El propósito principal de este trabajo es profundizar en la caracterización de esta enfermedad y dar a conocer la congruencia que debe de existir entre la agudeza visual y la visión de colores en las neuropatías de este tipo; además, estimar sobre la base de este elemento la posible cifra de errores diagnósticos de dos grupos de pacientes con neuropatía optica epidérmica y en un tercer grupo de pacientes que no mejoraron con tratamiento, donde se reunieron 78 casos remitidos porque no mejoraban con tratamiento vitamínico. Los resultados demostraron congruencia entre el estado de afectación de la agudeza visual y la visión de colores en más del 90 % de los 960 casos de los grupos 1 y 2, con diagnóstico de neuropatía óptica epidémica comprobados por expertos, a diferencia de los casos del tercer grupo, en los que se detectó que el 96,1 % tuvieron de inicio falsos diagnósticos de esta enfermedad p < 0,01. Las enfermedades que con más frecuencia motivaron el error diagnóstico fueron: neuropatías de otro tipo, maculopatías, catarata polar posterior, histeria y simulación.

The optic form of the neuropathy epidemic that appeared in the last decade in Cuba has been discussed due to the possible hyperdiagnosis of the more than 22 000 notified cases. The main objective of this paper was to go deep into the characterization of this disease, to make known the congruency that should exist between the visual acuity and the vision of colors in the neuropathies of this type, and to estimate, on the basis of this element, the possible figure of diagnostic errors in 2 groups of patients with EON and of a third group of patients that did not improve with the treatment. In this group, there were 78 cases that were referred because they did not respond to vitamin therapy. The results showed congruency between the state of affection of visual acuity and the vision of colors in more than 90 % of the 960 cases from groups 1 and 2 with diagnosis of epidemic optical neuropathy confirmed by experts The results were different in the third group, where 96.1 % of the patients had false diagnoses of this disease since the beginning p 0.01. . The diseases leading to the diagnostic error more frequently were: neuropathies of other type, maculopathies, posterior polar cataract, hysteria and simulation.