Leber’s optic neuropathy associated with disseminated white matter disease: A case report and review

A Comprehensive Review of Leber Hereditary Optic Neuropathy and Its Association with Multiple Sclerosis-Like Phenotypes Known as Harding's Disease

Leber Hereditary Optic Neuropathy (LHON) stands as a distinctive maternally inherited mitochondrial disorder marked by painless, subacute central vision loss, primarily affecting young males. This review covers the possible relationship between LHON and multiple sclerosis (MS), covering genetic mutations, clinical presentations, imaging findings, and treatment options. LHON is associated with mutations in mitochondrial DNA (mtDNA), notably m.11778G>A, m.3460G>A, and m.14484T>C, affecting complex I subunits. Beyond ocular manifestations, LHON can go beyond the eye into a multi-systemic disorder, showcasing extraocular abnormalities. Clinical presentations, varying in gender prevalence and outcomes, underscore the nature of mitochondrial optic neuropathies. Hypotheses exploring the connection between LHON and MS encompass mitochondrial DNA mutations triggering neurological diseases, immunologically mediated responses inducing demyelination, and the possibility of coincidental diseases. The research on mtDNA mutations among MS patients sheds light on potential associations with specific clinical subgroups, offering a unique perspective into the broader landscape of MS. Imaging findings, ranging from white matter alterations to cerebrospinal fluid biomarkers, further emphasize shared pathological processes between LHON-MS and classical MS. This comprehensive review contributes to the understanding of the complex relationship between LHON and MS.

Leber's Hereditary Optic Neuropathy Plus Causing Recurrent Myelopathy due to an MT-DN1 Mutation at G3635A

A 51-year-old man with known Leber's hereditary optic neuropathy (LHON) presented with worsening lower extremity weakness and numbness. Following an episode of myelopathy two years before, he had been ambulating with a walker but over two weeks became wheelchair bound. He also developed a sensory level below the T4 dermatome to light touch, pinprick, and vibration. MRI of his cervical and thoracic spine showed a nonenhancing T2 hyperintense lesion extending from C2 to T12. At his presentation two years earlier, he was found to have a longitudinally extensive myelopathy attributed to his LHON. Genetic testing revealed a 3635 guanine to adenine mutation. MRI at that presentation demonstrated a C1-T10 lesion involving the central and posterior cord but, unlike the new lesion, did not involve the ventral and lateral horns. Given the similarity to his prior presentation and a negative evaluation for alternative etiologies, he was thought to have recurrent myelopathy secondary to Leber's Plus. To our knowledge, recurrent myelopathy due specifically to the G3635A mutation in Leber's Plus has not been reported previously.

Mitochondrial Mutations in Multiple Sclerosis Patients with Atypical Optic Neuropathy

BACKGROUND

Multiple sclerosis-related optic neuritis is mostly associated with good recovery. The aim of this study was to investigate the causes of progressive visual worsening in multiple sclerosis patients despite treatment.

METHODS

We retrospectively reviewed the medical records of multiple sclerosis patients with optic neuritis admitted to the ward of our Neurology Department between 2001 and 2020. The patients with unilateral/bilateral progressive visual loss or non-substantial recovery of visual acuity were screened for genetic testing for Leber's hereditary optic neuropathy.

RESULTS

Of 1014 multiple sclerosis patients, 411 (39%) reported having optic neuritis. During follow-up, 11 patients manifested atypical characteristics of multiple sclerosis-related optic neuritis (presence of one of the following clinical findings: bilateral simultaneous or sequential eye involvement, progressive visual loss, or no response to corticosteroids during hospitalization), while others presented with typical multiple sclerosis-related optic neuritis. Those multiple sclerosis patients with atypical characteristics of optic neuritis were screened for other possible etiologies of optic neuropathy. We found pathogenic mitochondrial mutations in 5 patients with multiple sclerosis in our study group.

CONCLUSION

In our study group, the prevalence of mitochondrial mutations among all multiple sclerosis patients with optic neuritis was 0.12%. We strongly recommend investigating Leber's hereditary optic neuropathy mutations in MS patients if they suffer from severe or bilateral visual loss without recovery during follow-up. Because Leber's hereditary optic neuropathy mitochondrial mutations indicate relatively poor visual prognosis and have important implications for genetic counseling.

Occult primary white matter impairment in Leber hereditary optic neuropathy

BACKGROUND AND PURPOSE

Leber hereditary optic neuropathy (LHON) is a disease maternally inherited from mitochondria that predominantly impairs the retinal ganglion cells and their axons. To identify whether occult brain white matter (WM) impairment is involved, a voxel-based analysis (VBA) of diffusion metrics was carried out in LHON patients with normal-appearing brain parenchyma.

METHODS

Fifty-four symptomatic LHON patients (including 22 acute LHON with vision loss for ≤12 months, and 32 chronic LHON) without any visible brain lesions and 36 healthy controls (HCs) were enrolled in this study. VBA was applied to quantify the WM microstructural changes of LHON patients. Finally, the associations of the severity of WM impairment with disease duration and ophthalmologic deficits were assessed.

RESULTS

Compared with the HCs, the average retinal nerve fiber layer (RNFL) thickness was significantly reduced in patients with chronic LHON, whereas it was increased in patients with acute LHON (p < 0.05, corrected). VBA identified significantly decreased fractional anisotropy widely in WM in both the acute and chronic LHON patients, including the left anterior thalamic radiation and superior longitudinal fasciculus, and bilateral corticospinal tract, dentate nuclei, inferior longitudinal fasciculus, forceps major, and optic radiation (OR; p < 0.05, corrected). The integrity of most WM structures (except for the OR) was correlated with neither disease duration nor RNFL thickness (p > 0.05, corrected).

CONCLUSIONS

Occult primary impairment of widespread brain WM is present in LHON patients. The coexisting primary and secondary WM impairment may jointly contribute to the pathological process of LHON.

Leber’s hereditary optic neuropathy with diffuse white matter changes mimicking gliomatosis cerebri: illustrative case

BACKGROUIND

Leber’s hereditary optic neuropathy (LHON) is a mitochondrial disease characterized by bilateral severe subacute central vision loss and a mutation in the mitochondrial DNA (mtDNA). The findings on cranial magnetic resonance imaging of patients with LHON vary from subtle to multiple white matter changes. However, they rarely present with diffuse infiltrative white matter changes.

OBSERVATIONS

The authors reported a case with diffuse white matter changes mimicking gliomatosis cerebri (GC). The histological findings included only mild glial hyperplasia without immunohistochemical positivity, supporting the diagnosis of glial tumors. Analysis of mtDNA obtained from the blood and brain tissue revealed mutation of m.11778G>A in the NADH dehydrogenase 4 gene, which confirmed the case as LHON. Immunohistochemistry of the brain tissue revealed 8-hydroxy-2′-deoxyguanosine positivity, suggesting the presence of oxidative stress.

LESSONS

LHON is extremely difficult to diagnose unless one suspects or knows the disease. The present case brings attention not only to LHON but also to other mtDNA-mutated diseases that need to be considered with diffuse white matter changes or GC.

Leber's hereditary optic neuropathy following unilateral painful optic neuritis: a case report

BACKGROUND

Leber's hereditary optic neuropathy (LHON) is a maternally inherited mitochondrial disease, characterized by acute or subacute, painless, bilateral visual loss. LHON is often misdiagnosed as optic neuritis at an early stage because of the similarity of their clinical presentation. To date, there has been no reported case of actual optic neuritis and LHON in one patient.

CASE PRESENTATION

A 40-year-old, healthy man was referred to our clinic with acute painful visual loss in the right eye for 2 weeks. In the right eye, visual acuity decreased to 20/40, and the Ishihara colour test score was 8/14 with a relative afferent pupillary defect. Optic disc swelling was found only in the right eye, and magnetic resonance imaging revealed enhancement of the the right optic nerve, consistent with optic neuritis. After receiving 1 g of intravenous methylprednisolone daily for three days, his ocular pain resolved, and visual acuity improved to 20/20 within 2 weeks. Seven months later, the patient developed acute painless visual loss in the right eye. Visual acuity decreased to 20/200 in the right eye. There was no response to the intravenous methylprednisolone therapy at that time. Eight months later, he developed subacute painless visual loss in the left eye. Genetic testing for LHON was performed and revealed the pathologic mtDNA 11778 point mutation.

CONCLUSIONS

We report a case with painful unilateral optic neuritis preceding the onset of LHON. Even if a typical optic neuritis patient has completely recovered from steroid treatment once in the past, it is advisable to keep in mind the possibility of LHON if acute or subacute loss of vision subsequently or simultaneously occurs in both eyes and does not respond to steroids.

Leber hereditary optic neuropathy plus dystonia, and transverse myelitis due to double mutations in MT-ND4 and MT-ND6

Leber hereditary optic neuropathy (LHON) typically presents as painless central or centrocecal scotoma and is due to maternally inherited mitochondrial DNA (mtDNA) mutations. Over 95% of LHON cases are caused by one of three mtDNA "common" point mutations: m.3460G>A, m.11778G>A, or m.14484T>C, which are all in genes encoding structural subunits of complex I of the respiratory chain. Intriguing features of LHON include: incomplete penetrance, tissue specificity, and male predominance, indicating that additional genetic or environmental factors are modulating the phenotypic expression of the pathogenic mtDNA mutations. However, since its original description as a purely ophthalmological disorder, LHON has also been linked to multisystemic conditions with variable neurological, cardiac, and skeletal abnormalities. Although double "common" mutations have been reported to cause LHON and LHON-plus, they are extremely rare. Here, we present a patient with an unusual double point mutation (m.11778 G>A and m.14484T>C) with a multisystemic LHON-plus phenotype characterized by: optic neuropathy, ptosis, ataxia, dystonia, dysarthria, and recurrent extensive transverse myelitis.

Cardiovascular Manifestations of Mitochondrial Disease

Genetic mitochondrial cardiomyopathies are uncommon causes of heart failure that may not be seen by most physicians. However, the prevalence of mitochondrial DNA mutations and somatic mutations affecting mitochondrial function are more common than previously thought. In this review, the pathogenesis of genetic mitochondrial disorders causing cardiovascular disease is reviewed. Treatment options are presently limited to mostly symptomatic support, but preclinical research is starting to reveal novel approaches that may lead to better and more targeted therapies in the future. With better understanding and clinician education, we hope to improve clinician recognition and diagnosis of these rare disorders in order to improve ongoing care of patients with these diseases and advance research towards discovering new therapeutic strategies to help treat these diseases.

Leber Hereditary Optic Neuropathy and Longitudinally Extensive Transverse Myelitis

Leber Hereditary Optic Neuropathy is an inherited optic neuropathy caused by mitochondrial DNA point mutations leading to sudden, painless loss of vision. We report a case of an 8-year-old boy presenting with a radiological phenotype of longitudinally extensive transverse myelitis on a background of severe visual impairment secondary to Leber Hereditary Optic Neuropathy (LHON). He was found to have dual mitochondrial DNA mutations at 14484 (MTND6 gene) and 4160 (MTND1 gene) in a family with a severe form of LHON characterised by not only an unusually high penetrance of optic neuropathy, but also severe extra-ocular neurological complications. The m.14484T>C mutation is a common LHON mutation, but the m.4160T>C mutation is to our knowledge not reported outside this family and appears to drive the neurological manifestations. To our knowledge there have been no previous reports of spinal cord lesions in children with LHON.

Clinical features of MS associated with Leber hereditary optic neuropathy mtDNA mutations

Objective:

To determine whether the association between multiple sclerosis (MS) and Leber hereditary optic neuropathy (LHON) (known as “Harding disease”) is a chance finding, or the 2 disorders are mechanistically linked.

Methods:

We performed a United Kingdom–wide prospective cohort study of prevalent cases of MS with LHON mitochondrial DNA (mtDNA) mutations. The new cases were compared with published cases, enabling a comprehensive clinical description. We also performed a meta-analysis of studies screening patients with MS for LHON mtDNA mutations to find evidence of a genetic association.

Results:

Twelve new patients were identified from 11 pedigrees, and 44 cases were identified in the literature. The combined cohort had the following characteristics: multiple episodes of visual loss, predominance for women, and lengthy time interval before the fellow eye is affected (average 1.66 years), which is very atypical of LHON; conversely, most patients presented without eye pain and had a poor visual prognosis, which is unusual for optic neuritis associated with MS. The number of UK cases of LHON-MS fell well within the range predicted by the chance occurrence of MS and the mtDNA mutations known to cause LHON. There was no association between LHON mtDNA mutations and MS in a meta-analysis of the published data.

Conclusions:

Although the co-occurrence of MS and LHON mtDNA mutations is likely to be due to chance, the resulting disorder has a distinct phenotype, implicating a mechanistic interaction. Patients with LHON-MS have a more aggressive course, and prognostication and treatment should be guarded.

Multiple sclerosis and mitochondrial gene variations: a review

Multiple sclerosis (MS) is a debilitating disease of the central nervous system. Its etiology is still an unanswered enigma; its symptoms are varied and unpredictable; and there is no cure for it. Genetics has been introduced as a contributing factor to MS. Not only may MS stem from nuclear gene variations/mutations, but also it may arise from mitochondrial gene variations/mutations. The association of mitochondrial DNA variations/mutations with the pathogenesis of MS has, so far, been analyzed by several studies. This paper reviews the literature with regard to MS and corresponding mitochondrial DNA variations.

Atypical presentation of Leigh syndrome associated with a Leber hereditary optic neuropathy primary mitochondrial DNA mutation

Leber hereditary optic neuropathy (LHON) is caused by point mutations in mitochondrial DNA (mtDNA), and is characterized by bilateral, painless sub-acute visual loss that develops during the second decade of life. Here we report the case of a five year old girl who presented with clinical and neuroradiological findings reminiscent of Leigh syndrome but carried a mtDNA mutation m.11778G>A (p.R340H) in the MTND4 gene usually observed in patients with LHON. This case is unusual for age of onset, gender, associated neurological findings and evolution, further expanding the clinical spectrum associated with primary LHON mtDNA mutations.

Beyond the serotonin hypothesis: mitochondria, inflammation and neurodegeneration in major depression and affective spectrum disorders

For many years, a deficiency of monoamines including serotonin has been the prevailing hypothesis on depression, yet research has failed to confirm consistent relations between brain serotonin and depression. High degrees of overlapping comorbidities and common drug efficacies suggest that depression is one of a family of related conditions sometimes referred to as the "affective spectrum disorders", and variably including migraine, irritable bowel syndrome, chronic fatigue syndrome, fibromyalgia and generalized anxiety disorder, among many others. Herein, we present data from many different experimental modalities that strongly suggest components of mitochondrial dysfunction and inflammation in the pathogenesis of depression and other affective spectrum disorders. The three concepts of monoamines, energy metabolism and inflammatory pathways are inter-related in many complex manners. For example, the major categories of drugs used to treat depression have been demonstrated to exert effects on mitochondria and inflammation, as well as on monoamines. Furthermore, commonly-used mitochondrial-targeted treatments exert effects on mitochondria and inflammation, and are increasingly being shown to demonstrate efficacy in the affective spectrum disorders. We propose that interactions among monoamines, mitochondrial dysfunction and inflammation can inspire explanatory, rather than mere descriptive, models of these disorders.

[Hereditary optic atrophies]

INTRODUCTION

Hereditary optic neuropathies, resulting from retinal ganglion cell degeneration, are a heterogeneous group of diseases ranging from asymptomatic forms to legal blindness.

STATE OF KNOWLEDGE

Two most frequent phenotypes are Kjer's disease, an autosomal dominant optic atrophy caused by OPA1 gene mutations, and Leber's disease due to maternally inherited mitochondrial DNA mutations.

PROSPECTS AND CONCLUSION

Both optic neuropathies usually isolated are sometimes associated with extraocular symptoms, especially neurological symptoms, thus justifying a systematic neurological evaluation and brain imaging.

Language skills in a child with Leber hereditary optic neuropathy following intrathecal chemotherapy for acute lymphoblastic leukemia

The language skills of a male child with Leber hereditary optic neuropathy (LHON) and coincidentally treated for acute lymphoblastic leukemia (ALL) with intrathecal chemotherapy at the age of 3 years 8 months were comprehensively evaluated twice over a 6-month period approximately 5&#x00BD; years after diagnosis of ALL. Despite marked chemotherapy-related leukoencephalopathic changes documented on magnetic resonance imaging, the child presented with stable language skills, which were generally average to above-average based on the normative data from a comprehensive language test battery. In light of the coincidental presentation in the child of a diagnosis of LHON, which may lead to serious vision impairment and increased vulnerability to drug neurotoxicity, coupled with a history of central nervous system (CNS)-directed treatment for ALL resulting in progressive white matter pathology, the study highlights the importance of ongoing monitoring of the child's language development throughout his adolescent years.

Ophthalmologic manifestations commonly misdiagnosed as demyelinating events in multiple sclerosis patients

PURPOSE OF REVIEW

Multiple sclerosis may affect both afferent and efferent visual pathways, and sometimes physicians err on ordinary ophthalmologic diagnosis due to overlapping symptoms between demyelinating and nondemyelinating visual diseases. The present article highlights nondemyelinating ocular occurrences due to physiologic or other pathologic processes that may appear in some patients.

RECENT FINDINGS

Optic neuritis is representative of the most common and best-studied demyelinating visual occurrence in multiple sclerosis. However, other nondemyelinating visual disturbances also seen in the general population may be erroneously interpreted as being part of the underlying disease. This comparison has not been documented and may be helpful to overcome such difficulties.

SUMMARY

Based on clinical history and some strategies of ophthalmologic examination, physicians can achieve the correct diagnosis. Some clinical situations, however, may be challenging and a multidisciplinary approach in the care of multiple sclerosis is warranted.

Blood pressure treatment in acute ischemic stroke: a review of studies and recommendations

PURPOSE OF REVIEW

Elevated blood pressure (BP) is frequent in patients with acute ischemic stroke. Pathophysiological data support its usefulness to maintain adequate perfusion of the ischemic penumba. This review article aims to summarize the available evidence from clinical studies that examined the prognostic role of BP during the acute phase of ischemic stroke and intervention studies that assessed the efficacy of active BP alteration.

RECENT FINDINGS

We found 34 observational studies (33,470 patients), with results being inconsistent among the studies; most studies reported a negative association between increased levels of BP and clinical outcome, whereas a few studies showed clinical improvement with higher BP levels, clinical deterioration with decreased BP, or no association at all. Similarly, the conclusions drawn by the 18 intervention studies included in this review (1637 patients) were also heterogeneous. Very recent clinical data suggest a possible beneficial effect of early treatment with some antihypertensives on late clinical outcome.

SUMMARY

Observational and interventional studies of management of acute poststroke hypertension yield conflicting results. We discuss different explanations that may account for this and discuss the current guidelines and pathophysiological considerations for the management of acute poststroke hypertension.

Multiple sclerosis. Part I: neuro-ophthalmic manifestations

PURPOSE OF REVIEW

This update includes topics relating to multiple sclerosis (MS) for the ophthalmologist.

RECENT FINDINGS

Interest in the ophthalmology of MS is highlighted by the substantial amount of original research presented at recent medical conferences. At the 2008 World Congress on Treatment and Research in Multiple Sclerosis, 33 of 898 abstract presentations related to ophthalmology. The most represented topics were optical coherence tomography (OCT) and radiology of the visual system (19/33 posters). The 2009 North American neuro-ophthalmologic society (NANOS) conference featured MS-related topics in 6 of 24 platform presentations. This article reviews recent advancements in the neuro-ophthalmology of MS.

SUMMARY

Multiple sclerosis results in various ophthalmic abnormalities. Optic neuritis is the most widely studied visual disturbance in MS, but other unusual visual manifestations such as Charles Bonnet syndrome or the Pulfrich phenomenon also occur. OCT is used to measure thickness of the retinal nerve fiber layer. Because thinning of this layer in MS represents axonal loss, OCT is being used to evaluate neuroprotective treatments. The efferent visual system, in particular the medial longitudinal fasciculus pathway, may be a way to measure body temperature-induced changes in MS.

Multiple sclerosis associated with Leber's Hereditary Optic Neuropathy

The cause of multiple sclerosis is unknown although it is recognised to involve an inflammatory process associated with demyelinating plaques and more widespread neurodegeneration. It appears to have become progressively more common in females which is further discussed in this issue, and genetic factors, as identified to date, appear to play only a moderate role. One curious observation is that Leber's Hereditary Optic Neuropathy (LHON), a rare genetic syndrome, presents clinically overwhelmingly in males, but can be associated with an MS-like illness and when it does it occurs mainly in females. It is interesting to examine this further to assess if this could give us any clues as to the pathogenesis of MS.