A case of mitochondrial myopathy and chronic progressive external ophthalmoplegia. / çº¿ç²’ä½“è‚Œç— åˆå¹¶æ ¢æ€§è¿›è¡Œæ€§çœ¼å¤–è‚Œéº»ç—¹1例（英文）.

Mitochondrial myopathy is a group of multi-system diseases in which mitochondrial DNA (mtDNA) or nuclear DNA (nDNA) defects lead to structural and functional dysfunction of mitochondria. The clinical manifestations of mitochondrial myopathy are complex and varied, and the testing for mtDNA and nDNA is not widely available, so misdiagnosis or missed diagnosis is common. Chronic progressive external ophthalmoplegia (CPEO) is a common type of mitochondrial myopathy, which is characterized by blepharoptosis. Here we report a 38-year-old female with mitochondrial myopathy presented with chronic numbness and weakness of the limbs, accompanied by blepharoptosis that was recently noticed. Laboratory and head magnetic resonance imaging (MRI) examinations showed no obvious abnormalities. Muscle and nerve biopsies showed characteristic ragged red fibers (RRFs) and large aggregates of denatured mitochondria. Testing for mtDNA and nDNA showed a known mutation c.2857C>T (p.R953C) and a novel variant c.2391G>C (p.M797I) in the polymerase gamma (POLG)gene, so the patient was diagnosed as mitochondrial myopathy. Clinicians should pay more attention to long-term unexplained skeletal muscle diseases with recent onset blepharoptosis. Histopathologic examination and genetic testing are of great value in the early diagnosis and therapeutic intervention.

Kearns-Sayre syndrome with rare imaging finding of SLC25A4 Mutation.

Kearns-Sayre Syndrome (KSS) is a subtype of chronic progressive external ophthalmoplegia (CPEO). In this case, A 21-year-old man diagnosed with KSS, and presented with chronic progressive blepharoptosis (ptosis) and external ophthalmoplegia, diffuse depigmentation of the retinal pigment epithelium, and cerebellar ataxia, with a cerebrospinal fluid protein of 254 mg/dL, was reported. Genetic screening revealed a novel mutated gene in SLC25A4 in the patient as well as in his mother: NM_001151:c.170G>C in exon 2. Its imaging finding is a characteristic progressive atrophy of the right cerebellar hemisphere. In conclusion, we found a case of KSS with a novel mutated gene in SLC25A4: NM_001151:c.170G>C in exon 2 as the pathogenic mechanism, and found that KSS can be caused only when the proportion of mutations in the SLC25A4 gene reach a certain degree, and the patient with KSS showed a unique cranial imaging feature of unilateral progressive cerebellar atrophy.

Acetyl-CoA-driven respiration in frozen muscle contributes to the diagnosis of mitochondrial disease.

BACKGROUND: Freezing human biopsies is common in clinical practice for storage. However, this technique disrupts mitochondrial membranes, hampering further analyses of respiratory function. To contribute to laboratorial diagnosis of mitochondrial diseases, this study sought to develop a respirometry approach using O2k (Oroboros Ins.) to measure the whole electron transport chain (ETC) activity in homogenates of frozen skeletal muscle biopsies. PATIENTS AND METHODS: We enrolled 16 patients submitted to muscle biopsy in the process of routine diagnostic investigation: four with mitochondrial disease and severe mitochondrial dysfunction; seven with exercise intolerance and multiple deletions of mitochondrial DNA, presenting mild to moderate mitochondrial dysfunction; five without mitochondrial disease, as controls. Whole homogenates of muscle fragments were prepared using grinder-type equipment. O2 consumption rates were normalized using citrate synthase activity. RESULTS: Transmission electron microscopy confirmed mitochondrial membrane discontinuation, indicating increased permeability of mitochondrial membranes in homogenates from frozen biopsies. O2 consumption rates in the presence of acetyl-CoA lead to maximum respiratory rates sensitive to rotenone, malonate and antimycin. This protocol of acetyl-CoA-driven respiration (ACoAR), applied in whole homogenates of frozen muscle, was sensitive enough to identify ETC abnormality, even in patients with mild to moderate mitochondrial dysfunction. We demonstrated adequate repeatability of ACoAR and found significant correlation between O2 consumption rates and enzyme activity assays of individual ETC complexes. CONCLUSIONS: We present preliminary data on a simple, low cost and reliable procedure to measure respiratory function in whole homogenates of frozen skeletal muscle biopsies, contributing to diagnosis of mitochondrial diseases in humans.

Progressive external ophthalmoplegia associated with novel MT-TN mutations.

OBJECTIVES: To describe two patients with progressive external ophthalmoplegia (PEO) and mitochondrial myopathy associated with mutations in mitochondrial DNA, encoding the tRNAAsn gene (MT-TN), which have not previously been published with clinical descriptions. MATERIALS & METHODS: Two unrelated patients with PEO were clinically examined. Muscle biopsy was performed and investigated by exome sequencing, enzyme histochemistry, and immunohistochemistry. The level of heteroplasmy was investigated in single muscle fibers and in other tissues. RESULTS: Patient 1 was a 52-year-old man with ptosis, PEO, and exercise intolerance since childhood. Muscle biopsy demonstrated mitochondrial myopathy with frequent cytochrome c oxidase (COX)-deficient fibers and a heteroplasmic mutation, m.5669G>A in the MT-TN gene, resulting in a substitution of a highly conserved C to T in the T stem of tRNAAsn . Patient 2 was a 66-year-old woman with ptosis, PEO, and exercise intolerance since many years. Muscle biopsy demonstrated mitochondrial myopathy with frequent COX-deficient fibers. She had a novel m.5702delA mutation in MT-TN, resulting in loss of a highly conserved U in the anticodon stem of tRNAAsn . Single fiber analysis in both cases showed highly significant differences in mutation load between COX-deficient and COX-normal fibers and a high threshold level for COX deficiency. The mutations were not found in blood, urine sediment or buccal cells. CONCLUSION: We describe two MT-TN mutations associated with PEO and mitochondrial myopathy, and their pathogenicity was demonstrated. Together with previous reports, the results indicate that MT-TN is a hot spot for mutations causing sporadic PEO.

Horizontal Gaze Palsy, Scoliosis, and Split Pons Sign in a 6-Year-Old Girl.

ABSTRACT: A 6-year-old girl presented with complaints of absent horizontal eye movements since birth. There was also associated progressive scoliosis for past 1 year. Neuroimaging revealed split pons sign, butterfly-shaped medulla, and prominent inferior olivary nuclei. The presence of congenital horizontal gaze palsy, childhood onset progressive scoliosis, and abnormal neuroimaging findings confirmed the diagnosis of horizontal gaze palsy with progressive scoliosis. This case highlights the importance of neuroimaging in a child presenting with horizontal gaze palsy and scoliosis that helped for starting early rehabilitation of the child, prevention of permanent vision loss, and parental counseling for future pregnancies.

Relapsing remitting multiple sclerosis in progressive external ophthalmoplegia: A report of two cases.

Evidence from genetic and pathologic studies suggests that mitochondrial dysfunction occurs in multiple sclerosis (MS). Furthermore, cases of MS have been reported in patients with mitochondrial disease. The phenotypic range of mitochondrial illness associating with MS is not yet well defined. In this report, we highlight two cases of patients with confirmed genetic mutations responsible for progressive external ophthalmoplegia who independently meet McDonald criteria for MS. Better characterization of the range of mitochondrial disease associated with MS may improve our understanding of MS disease pathophysiology.

The neuro-ophthalmology of inherited myopathies.

PURPOSE OF REVIEW: Inherited myopathies, and in particular mitochondrial myopathies, are heterogeneous disorders, and ocular manifestations may be the presenting feature or offer important diagnostic clues. The ophthalmologist may be key to diagnosis, facilitating recognition of associated potentially life-threatening organ manifestations and an integral part of multidisciplinary care. This review, focusing especially on mitochondrial myopathies, provides updates on clinical features, diagnosis and recent therapeutic developments. RECENT FINDINGS: Ptosis and/or ophthalmoplegia is present in over half of patients with mitochondrial disease, and associated clinical features imply specific genetic associations. Advances in next-generation sequencing have led to rapid evolution in the field, improving diagnosis rates, facilitating identification of novel genes, mutations and phenotypes, and providing important insights into disease mechanisms and therapeutic possibilities. Improved understanding of molecular mechanisms in inherited myopathies is enabling the development of experimental molecular therapies with clinical potential. SUMMARY: Genetic advances are driving progress in the field of inherited myopathies, influencing diagnosis, understanding of disease and development of therapies. Recognition of key features can impact diagnosis and management of these important conditions.

[Chronic Progressive External Ophthalmoplegia Ptosis: Problems with Diagnostics and Treatment]. / Ptosis bei chronisch progressiver externer Ophthalmoplegie: diagnostische Probleme und therapeutische Konsequenzen.

Ptosis is often the first symptom of chronic progressive external ophthalmoplegia (CPEO), a rare muscle disorder. As the disease progresses, it can lead to ocular motility defects. Ptosis is present in the early stages of the disease and can be corrected by levator surgery. Due to the rarity of CPEO (< 1% of ptosis patients), further diagnostic steps with muscle biopsy and genetic analysis of mitochondrial DNA are usually not considered in the early phase. Intraoperative abnormal observations during ptosis surgery and postoperative motility problems are signs of CPEO. If CPEO is confirmed, alternative surgical methods can correct the ptosis, like frontalis suspension.

False positive acetylcholine receptor antibodies in a case of unilateral chronic progressive external ophthalmoplegia: case report and review of literature.

METHODS: We present a rare case with atypical presenting features of unilateral CPEO with a false positive Acetylcholine Receptor Antibody (AchRA) test resulting in diagnostic delay. We illustrate the unilateral nature of this case and demonstrate the caveats of performing myogenic ptosis correction in such patients. We also discuss the differential diagnosis of false positive AchRA, a test commonly performed in the investigation of ptosis. RESULTS: A 34-year old female presented with a more than 3-year history of slowly-progressive, unilateral, right-sided restriction in eye movements and ptosis. Clinical examination showed EOM were grossly restricted in the right eye with a ptosis and normal in the left eye. Serum AchRA was positive on serum enzyme-linked immunosorbent assay (ELISA) however, following two months of oral pyridostigmine therapy there were no signs of clinical improvement. The initial serum sample sent was retested for AchRA by radio-immunoassay (RIA) which came back negative. Subsequently a muscle biopsy was requested which showed the presence of ragged red fibres. CONCLUSION: Unilateral ptosis and ophthalmoplegia is an unusual presentation for CPEO which characteristically produces bilateral symmetrical motility defects. In addition to Myasthenia Gravis elevated AchRA levels have been reported in other autoimmune conditions such as Primary biliary cirrhosis, Eaton Lambert syndrome and Graves's ophthalmopathy. We also highlight the superiority of RIA versus ELISA in the detection of AchRA and illustrate the diagnostic challenge of investigating and managing myogenic ptosis in this complex cohort of patients.

Horizontal Gaze Palsy and Progressive Scoliosis With ROBO 3 Mutations in Patients From Cape Verde.

Horizontal gaze palsy with progressive scoliosis (HGPPS) is a rare and autosomal recessive syndrome. We describe 2 cases of HGPPS which are the first documented in patients of African ancestry from an isolated population in Cape Verde. They demonstrated typical findings on neuro-ophthalmic examination and brain magnetic resonance imaging. One patient had novel heterozymous mutations of the ROB0 3 gene.

Extra-ocular muscle MRI in genetically-defined mitochondrial disease.

OBJECTIVES: Conventional and quantitative MRI was performed in patients with chronic progressive external ophthalmoplegia (CPEO), a common manifestation of mitochondrial disease, to characterise MRI findings in the extra-ocular muscles (EOMs) and investigate whether quantitative MRI provides clinically relevant measures of disease. METHODS: Patients with CPEO due to single mitochondrial DNA deletions were compared with controls. Range of eye movement (ROEM) measurements, peri-orbital 3 T MRI T1-weighted (T1w) and short-tau-inversion-recovery (STIR) images, and T2 relaxation time maps were obtained. Blinded observers graded muscle atrophy and T1w/STIR hyperintensity. Cross-sectional areas and EOM mean T2s were recorded and correlated with clinical parameters. RESULTS: Nine patients and nine healthy controls were examined. Patients had reduced ROEM (patients 13.3°, controls 49.3°, p < 0.001), greater mean atrophy score and increased T1w hyperintensities. EOM mean cross-sectional area was 43 % of controls and mean T2s were prolonged (patients 75.6 ± 7.0 ms, controls 55.2 ± 4.1 ms, p < 0.001). ROEM correlated negatively with EOM T2 (rho = -0.89, p < 0.01), whilst cross-sectional area failed to correlate with any clinical measures. CONCLUSIONS: MRI demonstrates EOM atrophy, characteristic signal changes and prolonged T2 in CPEO. Correlation between elevated EOM T2 and ROEM impairment represents a potential measure of disease severity that warrants further evaluation. KEY POINTS: Chronic progressive external ophthalmoplegia is a common clinical manifestation of mitochondrial disease. • Existing extra-ocular muscle MRI data in CPEO reports variable radiological findings. MRI confirmed EOM atrophy and characteristic signal changes in CPEO. EOM T2 was significantly elevated in CPEO and correlated negatively with ocular movements. EOM T2 represents a potential quantitative measure of disease severity in CPEO.

Progressive External Ophthalmoplegia.

Progressive external ophthalmoplegia (PEO), marked by progressive bilateral ptosis and diffuse reduction in ocular motility, represents a finding of mitochondrial myopathy rather than a true diagnosis. PEO often occurs with other systemic features of mitochondrial dysfunction that can cause significant morbidity and mortality. Accurate and early recognition of PEO is paramount for the optimal care of these patients. We present an evidence-based review of the presenting neuro-ophthalmic features, differential diagnosis, diagnostic tools, systemic implications, and treatment options for isolated PEO and other PEO-associated mitochondrial syndromes.

Chronic Progressive External Ophthalmoplegia in the Absence of Ptosis.

Classically defined as bilateral, symmetric, and progressive ophthalmoparesis with myopathic ptosis, chronic progressive external ophthalmoplegia (CPEO) rarely has been reported in the absence of ptosis. We describe 2 patients with CPEO and without ptosis who presented with binocular diplopia related to small-angle esodeviations, poor fusional amplitudes, and slow saccades. In both cases, hematological studies and neuroimaging ruled out alternative etiologies, whereas muscle biopsy showed findings of mitochondrial myopathy.

[Muscular Dystrophies Involving the Retinal Function]. / Netzhautbeteiligung bei Muskeldystrophien.

Muscular dystrophies are rare disorders, with an incidence of approx. 20 in 100 000. Some dystrophies also affect retinal or optic nerve function. In such cases, the ophthalmological findings may be critical for differential diagnosis or patient counseling. For example in Duchenne muscular dystrophy, where the alteration in retinal function seems to reflect cerebral involvement. Other important forms are mitochondrial and metabolic disorders, such as the Kearns-Sayre syndrome and the Refsum syndrome. Molecular genetic analysis has become a major tool for differential diagnosis, but may be complex and demanding. This article gives an overview of major muscular dystrophies involving retinal function and their genetic origin, in order to guide differential diagnosis.

Radiological features of horizontal gaze palsy with progressive scoliosis. An 'Aunt Minnie' diagnosis?

Horizontal gaze palsy with progressive scoliosis (HGPPS) is a rare autosomal recessive disorder characterized by congenital absence of normal horizontal eye movements and progressive scoliosis through childhood and adolescence. The characteristic radiological features in HGPPS are butterfly configuration of the medulla, split pons sign, selective volume loss of dorsomedial brainstem, relatively spared cerebellum, relatively prominent inferior olivary nucleus and absent posterior prominence of the facial colliculi and gracilis and cuneate nuclei. These radiological features are reflective of ROBO3 gene mutation required for hindbrain axon midline crossing. Awareness of this diagnosis is important as the radiological features are characteristic enough to be considered as a rare 'Aunt Minnie' and a radiologist may be the first one to raise the possibility of this diagnosis as in this case.

The clinical, myopathological, and genetic analysis of 155 Chinese mitochondrial ophthalmoplegia patients with mitochondrial DNA single large deletions.

BACKGROUND: Progressive external ophthalmoplegia (PEO) is a common subtype of mitochondrial encephalomyopathy. OBJECTIVE: The study aimed to investigate the relationship between mitochondrial DNA (mtDNA) abnormalities, muscle pathology, and clinical manifestations in Chinese patients with single large-scale mtDNA deletion presenting with PEO. METHODS: This is a retrospective single-center study. Patients with PEO who had a single large deletion in mitochondrial DNA were included in this study. The associations were analyzed between mtDNA deletion patterns, myopathological changes, and clinical characteristics. RESULTS: In total, 155 patients with mitochondrial PEO carrying single large-scale mtDNA mutations were enrolled, including 137 chronic progressive external ophthalmoplegia (CPEO) and 18 Kearns-Sayre syndrome (KSS) patients. The onset ages were 9.61 ± 4.12 in KSS and 20.15 ± 9.06 in CPEO. The mtDNA deletions ranged from 2225 bp to 9131 bp, with m.8470_13446del being the most common. The KSS group showed longer deletions than the CPEO group (p = 0.004). Additionally, a higher number of deleted genes encoding respiratory chain complex subunits (p = 0.001) and tRNA genes (p = 0.009) were also observed in the KSS group. A weak negative correlation between the mtDNA deletion size and ages of onset (p < 0.001, r = -0.369) was observed. The proportion of ragged red fibers, ragged blue fibers, and cytochrome c negative fibers did not correlate significantly with onset ages (p > 0.05). However, a higher percentage of abnormal muscle fibers corresponds to an increased prevalence of exercise intolerance, limb muscle weakness, dysphagia, and cerebellar ataxia. CONCLUSION: We reported a large Chinese cohort consisting of mitochondrial PEO patients with single large-scale mtDNA deletions. Our results demonstrated that the length and locations of mtDNA deletions may influence onset ages and clinical phenotypes. The severity of muscle pathology could not only indicate diagnosis but also may be associated with clinical manifestations beyond the extraocular muscles.

Horizontal gaze palsy with progressive scoliosis.

Horizontal gaze palsy with progressive scoliosis (HGPPS) is a rare autosomal recessive condition characterized by absence of abduction and adduction movements with intact vertical eye movements and progressive scoliosis. Patients usually present by mid-childhood with complaints of progressive scoliosis. The clinical diagnosis of HGPPS can be further confirmed by the ROBO3 gene mutation on chromosome number 11. We present 2 Indian siblings who were incidentally diagnosed with HGPPS with synergistic convergence on regular eye examination; diagnosis was confirmed by radiological and genetic testing.

Diagnosis of mitochondrial myopathies.

Mitochondria are ubiquitous organelles and play crucial roles in vital functions, most importantly, the oxidative phosphorylation and energy metabolism. Therefore, mitochondrial dysfunction can affect multiple tissues, with muscle and nerve preferentially affected. Mitochondrial myopathy is a common clinical phenotype, which is characterized by early fatigue and/or fixed muscle weakness; rhabdomyolysis can seldom occur. Muscle biopsy often identifies signs of diseased mitochondria by morphological studies, while biochemical analysis may identify respiratory chain deficiencies. The clinical, morphological and biochemical data guide molecular analysis. Being the mitochondrial function under the control of both mitochondrial DNA and nuclear DNA, the search for mitochondrial DNA mutations and mitochondrial DNA quantitation, may not be sufficient for the molecular diagnosis of mitochondrial myopathies. Approximately 1500 nuclear genes can affect mitochondrial structure and function and the targeting of such genes may be necessary to reach the diagnosis. The identification of causative molecular defects in nuclear or mitochondrial genome leads to the definite diagnosis of mitochondrial myopathy.