Alternative titles; symbols. LHON presents in midlife as acute or subacute central vision loss leading to central scotoma and blindness. The disease has been associated with many missense mutations in the mtDNA that can act autonomously or in association with each other to cause the disease. As pointed out by Riordan-Eva and Harding , although the plethora of mtDNA mutations identified in families with LHON had resulted in confusion as to the pathogenic significance of each mutation, it had been established that the 3 primary mutations at basepairs The correlation between the mutation and a good visual prognosis provides not only hope for affected patients, but also an approach for further research into the pathogenesis of LHON. Yu-Wai-Man et al.
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Neuromyelitis optica antibody in Leber hereditary optic neuropathy: case report. 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. High-risk neuromyelitis optica NMO syndrome is 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 LHON is a primarily hereditary disorder due to mutations of mitochondrial DNA mtDNA that affects all tissues of the body and its clinical presentation is tissue-specific for the optic nerve and, eventually, the spinal cord. Only two classical NMO cases have been described before and they both describe patients with the complete spectrum of the disease i. A year-old man presented complaints of painless, subacute onset of blurry vision in both eyes for two months.
The right eye was first affected and the fellow eye became involved in the following week. He noted his vision was progressively worsening over time. He denied any other visual symptoms.
Past ocular history was unremarkable. Past medical history included diabetes and hypertension. He had two maternal uncles with low vision. He underwent a first neuro-ophthalmic consultation two months after onset of symptoms. There was a left relative afferent pupillary defect. Slit lamp examination was unremarkable. Fundoscopic examination revealed bilateral disc pallor Figure 1. Neurologic examination was normal. Computerized visual fields revealed cecocentral scotoma on the right and absolute central scotoma on the left Figure 2.
His family history of low vision lead us to conduct a blood test, which confirmed the existence of heteroplasmic primary LHON mtDNA mutation. Other family members denied undergoing neuro-ophthalmic examination or any blood tests.
Brain and spinal cord MRI were normal. Not surprisingly, optical coherence tomography confirmed a profound bilateral decrease of the peripapilary retinal nerve fiber layer Figure 3. He underwent a five-day course of intravenous methylprednisolone with no visual improvement. Neuromyelitis optica has been distinguished from MS by the presence of optic neuritis that is usually bilateral, simultaneous, without complete visual recovery often followed by permanent visual loss.
Clinical findings that are also suggestive of NMO are longitudinally extensive spinal cord lesions with absent or unspecific brain imaging abnormalities, and often rapid progression to debility, and even death 3,4. High-risk syndrome for NMO should be suspected in isolated recurrent bilateral optic neuritis, or in recurring isolated longitudinally-extensive myelitis 5. Those patients are in high risk of developing the second index event that characterizes the full-spectrum of the disease.
This syndrome is also recognized as forme fruste or limited form of NMO. To help confirm the diagnosis there is also a serum antibody marker available named aquaporin-4 antibody. It binds selectively to the AQP4 water channel, a protein complex located in the astrocytic foot processes at the blood brain barrier. Because of the location of the antigen, it might be considered not only a marker, but actually the causative agent 4.
It should be noted that anti-AQP4 is the first water channel specific autoantibody to be identified. AQP4 is considered the predominant water channel in the brain and spinal cord, and also in the skeletal muscles 4,5.
The localization of AQP4 in the spinal cord is consistent with the immunopathology of NMO, which involves inflammation at both the gray and white matter regions, and for unknown reasons, it is largely restricted to the spinal cord and optic nerves 4. This finding was similar to that observed in other countries 6. Conversely, LHON is an mtDNA mutation disease whose clinical setting is confined to the optic nerve and, eventually, the spinal cord 7.
Pathogenic mtDNA mutations occur mainly in the homoplasmic state i. It is worth remembering that the severity of visual loss and the optic atrophy are unpredictable despite the mutation load.
This can be attributed to the impossibility of biopsying the target tissues i. Previous studies suggest the limited value of blood tests in predicting the degree of heteroplasmy in other tissues 9. It can be supposed that such patients should present enough mutant mtDNA load in the optic nerves to relapse the disease However, this is the first case report to demonstrate NMO antibody in LHON, and probably, more similar cases will be reported as NMO antibody test has increasingly been ordered in medical practice.
In conclusion, the case described herein as painless, subacute bilateral decreased vision, and poor visual recovery, accompanied by maternal history of low vision and seropositivity of mtDNA mutation confirmed the diagnosis of LHON.
Whether this is a fact or mere coincidence only prospective studies would help confirm, or rule out, this striking correlation. Ophthalmologists and neurologists should bear in mind the possibility of this uncommon clinical association.
Devic's neuromyelitis optica: a case with mitochondrial DNA mutations. Eur Neurol. Devic's neuromyelitis optica and mitochondrial DNA mutation: a case report. Neurol Sci. Weinshenker BG. Neuromyelitis optica: what it is and what it might be.
Erratum in: Lancet. Cross SA. Rethinking neuromyelitis optica Devic disease. J Neuroophthalmol. Lana-Peixoto MA. Devic's neuromyelitis optica: a critical review. Arq Neuropsiquiatr. Does mitochondrial DNA predispose to neuromyelitis optica Devic's disease? J Neurol Sci. Acta Ophthalmol Scand. A heteroplasmic LHON family: tissue distribution and transmission of the mutation. Am J Hum Genet. Segregation patterns and heteroplasmy prevalence in Leber's hereditary optic neuropathy.
Invest Ophthalmol Vis Sci. Correspondence address: Luciano M. Submitted for publication: June 20, Accepted for publication: March 21, Funding: No specific financial support was available for this study. Disclosure of potential conflicts of interest: L. All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License. Services on Demand Journal. Rua Casa do Ator, - cj. How to cite this article.
Leber's Hereditary Optic Neuropathy Website
Barnils N. Hospital Universitario de Bellvitge. Method: Two patients diagnosed of unilateral LHON were treated with megadoses of idebenone, vitamin C and riboflavin for one year. They were examined clinically before, during and after treatment.
Amaurose Congênita de Leber