Inhibition of autophagy curtails visual loss in a model of autosomal dominant optic atrophy.

In autosomal dominant optic atrophy (ADOA), caused by mutations in the mitochondrial cristae biogenesis and fusion protein optic atrophy 1 (Opa1), retinal ganglion cell (RGC) dysfunction and visual loss occur by unknown mechanisms. Here, we show a role for autophagy in ADOA pathogenesis. In RGCs expressing mutated Opa1, active 5' AMP-activated protein kinase (AMPK) and its autophagy effector ULK1 accumulate at axonal hillocks. This AMPK activation triggers localized hillock autophagosome accumulation and mitophagy, ultimately resulting in reduced axonal mitochondrial content that is restored by genetic inhibition of AMPK and autophagy. In C. elegans, deletion of AMPK or of key autophagy and mitophagy genes normalizes the axonal mitochondrial content that is reduced upon mitochondrial dysfunction. In conditional, RGC specific Opa1-deficient mice, depletion of the essential autophagy gene Atg7 normalizes the excess autophagy and corrects the visual defects caused by Opa1 ablation. Thus, our data identify AMPK and autophagy as targetable components of ADOA pathogenesis.

Autosomal dominant optic atrophy with OPA1 gene mutations accompanied by auditory neuropathy and other systemic complications in a Japanese cohort.

Purpose: This study aimed to describe the genetic and clinical characteristics of four Japanese patients with autosomal dominant optic atrophy (DOA) accompanied by auditory neuropathy and other systemic complications (i.e., DOA-plus disease). Methods: Four patients from four independent families underwent comprehensive ophthalmic and auditory examinations and were diagnosed with DOA-plus disease. The disease-causing gene variants in the OPA1 gene were identified by direct sequencing. The genetic and clinical data of 48 DOA patients without systemic complications-that is, with simple DOA-were compared to those of DOA-plus patients. Results: DOA-plus patients noticed a decrease in vision before the age of 14 and hearing impairment 3 to 13 years after the development of visual symptoms. Two patients had progressive external ophthalmoplegia, and one patient had vestibular dysfunction and ataxia. The DOA-plus phenotypes accounted for 13.3% (4/30) of the families with the OPA1 gene mutations. Each DOA-plus patient harbored one of the monoallelic mutations in the OPA1 gene: c.1334G>A, p.R445H, c.1618A>C, p.T540P, and c.892A>C, p.S298R. Missense mutations accounted for 100% (4/4) of the DOA-plus families and only 11.5% (3/26) of the families with simple DOA. Conclusions: All the patients with the DOA-plus phenotype carried one of the missense mutations in the OPA1 gene. They all had typical ocular symptoms and signs of DOA in their first or second decade, and other systemic complications-such as auditory neuropathy, vestibular dysfunction, and ataxia-followed the ocular symptoms. We should consider the occurrence of extraocular complications in cases with DOA, especially when they carry the missense mutations in the OPA1 gene.

Metabolic stroke in a patient with bi-allelic OPA1 mutations.

OPA1 related disorders include: classic autosomal dominant optic atrophy syndrome (ADOA), ADOA plus syndrome and a bi-allelic OPA1 complex neurological disorder. We describe metabolic stroke in a patient with bi-allelic OPA1 mutations. A twelve-year old girl presented with a complex neurological disorder that includes: early onset optic atrophy at one year of age, progressive gait ataxia, dysarthria, tremor and learning impairment. A metabolic stroke occurred at the age of 12 years. The patient was found to harbor a de novo heterozygous frame shift mutation c.1963_1964dupAT; p.Lys656fs (NM_015560.2) and a missense mutation c.1146A > G; Ile382Met (NM_015560.2) inherited from her mother. The mother, aunt, and grandmother are heterozygous for the Ile382Met mutation and are asymptomatic. The co-occurrence of bi-allelic mutations can explain the severity and the early onset of her disease. This case adds to a growing number of patients recently discovered with bi-allelic OPA1 mutations presenting with a complex and early onset neurological disorder resembling Behr syndrome. To the best of our knowledge metabolic stroke has not been described before as an OPA1 related manifestation. It is important to be aware of this clinical feature for a prompt diagnosis and consideration of available treatment.

A review of mitochondrial optic neuropathies: from inherited to acquired forms / Revisión de las neuropatías ópticas mitocondriales: de las formas hereditarias a las adquiridas

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 (AU)

En los últimos años, se ha incrementado el uso en la literatura del término neuropatía óptica mitocondrial (MON), para describir un grupo de neuropatías ópticas que presentan una disfunción mitocondrial en las células ganglionares de la retina (RGC). De manera interesante, las MON incluyen etiologías genéticas, tales como Neuropatía Óptica Hereditaria de Leber (LHON) y Atrofia Óptica Dominante (DOA), así como etiologías adquiridas derivadas del consumo de drogas, deficiencias nutricionales y etiologías mixtas. Independientemente de que la causa sea hereditaria o adquirida, los pacientes presentan las mismas manifestaciones clínicas, con pérdida selectiva de RGCs debido a la disfunción mitocondrial. Se están explorando diversas terapias novedosas para revertir o limitar el daño a las RGC. En este documento revisamos la patofisiología, las manifestaciones clínicas, los diagnósticos diferenciales, el tratamiento actual y los prometedores objetivos terapéuticos de las MON (AU)

Cherubism. A case report / Querubismo. Discusión de un caso

Cherubism is a rare disorder with autosomal dominant inheritance. It is classified as a benign fibro-osseous lesions and may involve either facial bone. Its typical dentofacial deformities are caused by mutations in the SH3BP2 gene. The protein encoded by SH3BP2 had a significant role in the regulation of osteoblasts and osteoclasts. Accordingly with the radiological findings, differential diagnoses includes fibrous dysplasia, giant cell granuloma, osteosarcoma, juvenile ossifying fibroma, fibrous osteoma, odontogenic cyst and hyperparathyroidism. The aim of the present report is twofold. First, we examine the importance of the proper management of these cases. Second, we describe this rare syndrome with the goal of proposing suitable treatments (AU)

El querubismo es una enfermedad rara. Presenta herencia autosómica dominante y es clasificada como una enfermedad fibroósea benigna. Las deformidades típicas de esta dolencia se deben a la alteración del gen SH3BP2 y pueden afectar a cualquier hueso del macizo facial. La proteína codificada por este gen es fundamental para el correcto funcionamiento de osteoblastos y osteoclastos. El diagnóstico diferencial debe incluir: displasia fibrosa, granuloma de células gigantes, osteosarcoma, fibroma osificante juvenil, fibroma osteoide e hiperparatiroidismo (AU)

Curiosidad: reflejo de estornudo fótico. Síndrome helio-oftálmico de estornudos compulsivos autosómico dominante / A curious fact: Photic sneeze reflex. Autosomical dominant compelling helio-ophthalmic outburst syndrome

OBJETIVO: Evaluar la implicación ocular en la fisiopatología del síndrome helio-oftálmico de estornudos compulsivos autosómico dominante (ACHOOs). MÉTODOS: Una familia de raza caucásica, que muestra las características clínicas de ACHOOs, fue interrogada. De toda la familia, 12 pacientes presentan reflejo fótico y fueron seleccionados. Se realiza una evaluación oftalmológica completa. RESULTADOS: Se encuentra una herencia autosómica dominante con penetrancia parcial. El 67% de los sujetos estudiados mostró algún grado de prominencia en los nervios corneales. No se encontraron otras alteraciones oculares. CONCLUSIONES: Los nervios corneales prominentes pueden tener asociación con el ACHOOs. Las otras estructuras del ojo estudiados no parecen desempeñar un papel en el ACHOOs. Se necesitan más estudios para comprender la fisiología del ACHOOs

OBJECTIVE: To assess ocular involvement in the pathophysiology of autosomal dominant compelling helio-ophthalmic outburst syndrome (ACHOOs). METHODS: An interview was conducted with a Caucasian family that showed clinical features of ACHOOs. Twelve of them had photic reflex and were recruited. A complete eye evaluation was made. RESULTS: A dominant autosomal inheritance with mild penetrance was demonstrated, with 67% of the studied subjects showing some degree of prominent corneal nerves. No other eye changes were found. CONCLUSIONS: Prominent corneal nerves may be associated with ACHOOs. The other eye structures studied do not seem to play a role in ACHOOs. Further studies are needed to understand the physiology of the ACHOOs

Retinal vessel diameters decrease with macular ganglion cell layer thickness in autosomal dominant optic atrophy and in healthy subjects.

PURPOSE: To investigate retinal trunk vessel diameters in subjects with autosomal dominant optic atrophy (ADOA) and mutation-free healthy relatives. METHODS: This cross-sectional study included 52 ADOA patients with the optic atrophy 1 (OPA1) exon 28 (c.2826_2836delinsGGATGCTCCA) mutation (age 8.6-83.5 years) (best-corrected visual acuity (BCVA) 8-94 Early Treatment Diabetic Retinopathy Study (ETDRS) letters) and 55 mutation-free first-degree healthy relatives (age 8.9-68.7 years, BCVA 80-99). Analysis of fundus photographs provided integrated magnification-corrected measures of retinal vessel diameters (central retinal artery equivalent, CRAE, and central retinal vein equivalent, CRVE). Statistical analysis was corrected for age, gender, spherical equivalent refraction, axial length and mean arterial blood pressure (MABP) in a mixed model analysis. RESULTS: Retinal arteries and veins were thinner in ADOA than in healthy controls (CRAE (mean ± 2 standard deviations (SD)) 153.9 ± 41.0 µm and CRVE 236.1 ± 42.0 µm in ADOA, CRAE 172.5 ± 25.0 µm (p = 0.0004) and CRVE 254.2 ± 37.6 µm (p = 0.0019) in healthy controls). MABP was comparable in the two groups (p = 0.18), and in both groups, CRAE decreased with increasing MABP (p = 0.01 and p < 0.0001, respectively). In ADOA, CRAE and CRVE decreased with age (p = 0.011 and p = 0.020, respectively) and CRAE decreased with decreasing BCVA (p = 0.011). In patients with ADOA and in healthy controls, CRAE decreased with decreasing average macular ganglion cell-inner plexiform layer (GC-IPL) thickness (p = 0.0017 and p = 0.0057, respectively). CONCLUSION: Narrow retinal arteries and veins were associated not only with the severity of ADOA but with ganglion cell volume in patients with ADOA and in healthy subjects. This suggests that narrow vessels are a consequence rather than the cause of inner retinal hypoplasia or atrophy, although longitudinal studies are needed to confirm this hypothesis.

Unexplained gastrointestinal symptoms: think mitochondrial disease.

Defects in mitochondrial function are increasingly recognised as central to the pathogenesis of many diseases, both inherited and acquired. Many of these mitochondrial defects arise from abnormalities in mitochondrial DNA and can result in multisystem disease, with gastrointestinal involvement common. Moreover, mitochondrial disease may present with a range of non-specific symptoms, and thus can be easily misdiagnosed, or even considered to be non-organic. We describe the clinical, histopathological and genetic findings of six patients from three families with gastrointestinal manifestations of mitochondrial disease. In two of the patients, anorexia nervosa was considered as an initial diagnosis. These cases illustrate the challenges of both diagnosing and managing mitochondrial disease and highlight two important but poorly understood aspects, the clinical and the genetic. The pathophysiology of gastrointestinal involvement in mitochondrial disease is discussed and emerging treatments are described. Finally, we provide a checklist of investigations for the gastroenterologist when mitochondrial disease is suspected.

High-resolution en face images of microcystic macular edema in patients with autosomal dominant optic atrophy.

The purpose of this study was to investigate the characteristics of microcystic macular edema (MME) determined from the en face images obtained by an adaptive optics (AO) fundus camera in patients with autosomal dominant optic atrophy (ADOA) and to try to determine the mechanisms underlying the degeneration of the inner retinal cells and RNFL by using the advantage of AO. Six patients from 4 families with ADOA underwent detailed ophthalmic examinations including spectral domain optical coherence tomography (SD-OCT). Mutational screening of all coding and flanking intron sequences of the OPA1 gene was performed by DNA sequencing. SD-OCT showed a severe reduction in the retinal nerve fiber layer (RNFL) thickness in all patients. A new splicing defect and two new frameshift mutations with premature termination of the Opa1 protein were identified in three families. A reported nonsense mutation was identified in one family. SD-OCT of one patient showed MME in the inner nuclear layer (INL) of the retina. AO images showed microcysts in the en face images of the INL. Our data indicate that AO is a useful method to identify MME in neurodegenerative diseases and may also help determine the mechanisms underlying the degeneration of the inner retinal cells and RNFL.