Pathogenic Variants in the Myosin Chaperone UNC-45B Cause Progressive Myopathy with Eccentric Cores.

The myosin-directed chaperone UNC-45B is essential for sarcomeric organization and muscle function from Caenorhabditis elegans to humans. The pathological impact of UNC-45B in muscle disease remained elusive. We report ten individuals with bi-allelic variants in UNC45B who exhibit childhood-onset progressive muscle weakness. We identified a common UNC45B variant that acts as a complex hypomorph splice variant. Purified UNC-45B mutants showed changes in folding and solubility. In situ localization studies further demonstrated reduced expression of mutant UNC-45B in muscle combined with abnormal localization away from the A-band towards the Z-disk of the sarcomere. The physiological relevance of these observations was investigated in C. elegans by transgenic expression of conserved UNC-45 missense variants, which showed impaired myosin binding for one and defective muscle function for three. Together, our results demonstrate that UNC-45B impairment manifests as a chaperonopathy with progressive muscle pathology, which discovers the previously unknown conserved role of UNC-45B in myofibrillar organization.

Concurrent positive anti-3-hydroxy-3-methylglutaryl-coenzyme a reductase antibody with reducing body myopathy: Possible double trouble.

Anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase myopathy is less common in children but has been associated with more favorable prognosis than adult patients after immunotherapies. We report anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase antibody positivity in a 6-year-old boy with progressive muscle weakness, scoliosis, spinal rigidity, multiple joint contractures, mild left ventricular hypertrophy, and elevated serum creatine kinase. In contrast to most of previously reported pediatric anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase myopathy, he showed little response to immunotherapies. Muscle biopsy contained changes suggestive of myofiber necrosis and regeneration and reducing bodies. The diagnosis of reducing body myopathy was later confirmed by reported c.368A>G (p.His123Arg) mutation in the FHL1 gene. Although the level of association between these two conditions is still inconclusive, this is the first report of concurrent positive anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase antibody with reducing body myopathy emphasizing the possibility of co-occurrence of immune mediated necrotizing myopathy and muscular dystrophy and importance of comprehensive diagnostic investigations in unusual cases.

Impact of muscle biopsy on diagnosis and management of children with neuromuscular diseases: A 10-year retrospective critical review.

BACKGROUND: Muscle biopsy facilitates morphologic, biochemical, and ultrastructural analysis of muscle for the purpose of making definitive neuromuscular diagnosis. However, muscle biopsy is an expensive, invasive, time-consuming, and resource-dependent procedure. The need for general anesthesia in children also increases the risks associated with this procedure. The aim of this study was to investigate the benefits of muscle biopsies performed over a 10-year period, with a focus on indications, suspected and histopathologic diagnosis, and impact on diagnosis and management decisions. METHODS: We retrospectively reviewed results of muscle biopsies performed in children at our center during the 2004 to 2014 study period. Clinical presentations, biopsy complications, pathologic results, and changes in management decision were reviewed and analyzed. RESULTS: Biopsies from 92 patients were included. Mean age of patients was 7.1years, and 66.3% were male. There were no perioperative complications, and definitive diagnosis was made in 74 patients. Regardless of whether pathologic changes were found or not, information gained from muscle biopsy significantly impacted prognosis and subsequent genetic counseling. CONCLUSIONS: Muscle biopsy is a safe and useful diagnostic tool in children suspected of having neuromuscular diseases, especially in those with muscle diseases. Definitive pathologic diagnosis helps to optimize treatment, counseling, and surveillance. THE TYPE OF STUDY AND LEVEL OF EVIDENCE: Study of diagnostic test: level 1.

High Carbonic Anhydrase-9 Expression Identifies a Subset of 1p/19q Co-Deletion and Favorable Prognosis in Oligodendroglioma.

OBJECTIVE: To investigate the relationship between 3 hypoxic markers, carbonic anhydrase-9 (CA-9), hypoxia-inducible factor (HIF)-1α, and HIF-2α and the traditional genetic markers, deletions of chromosomes 1p and 19q and Isocitrate dehydrogenase 1 (IDH1) R132H mutation in oligodendrogliomas. METHODS: Thirty-one oligodendrogliomas (27 World Health Organization Grade [WHO] II and 4 WHO Grade III) were processed into tissue microarray. Fluorescence in situ hybridization was exploited to detect chromosome deletion, whereas immunohistochemistry was performed to assess IDH1R132H mutation, CA-9, HIF-1α, and HIF-2α expression. RESULTS: The frequencies of 1p/19q co-deletion and IDH1 R132H mutation were 68% and 71%, respectively. High expression of CA-9 was observed in 42% and was associated with longer survival (P = 0.04) in WHO Grade II oligodendroglioma. High CA-9 expression also identified 62% of 1p/19q-codeleted oligodendroglioma (P = 0.001). In addition, all tumors with high CA-9 expression displayed 1p/19q-codeletion. HIF-1α and HIF-2α provided no additional prognostic value for survival. CONCLUSIONS: High expression of CA-9, a marker for hypoxia and acidosis, is associated with favorable prognosis in oligodendroglioma. In addition, it may serve as a simple screening test for 1p/19q co-deletion if validated in larger cohorts.

Ophthalmoplegia in congenital neuromuscular disease with uniform type 1 fiber.

Congenital neuromuscular disease with uniform type 1 fiber (CNMDU1) is a rare type of congenital myopathy. It is characterized by early onset of symptoms, mild proximal muscle weakness, hyporeflexia or areflexia, normal serum creatine kinase (CK) levels and myopathic electromyography finding, uniform type 1 fibers, and nonprogression. We report a 2-year-old boy who presented with congenital hypotonia, breathing and feeding difficulty, myopathic facies, proximal muscle weakness, ptosis, total external ophthalmoplegia and delayed motor developmental milestones. Normal serum muscle enzyme and short duration of motor unit potentials on electromyography were noted. Muscle biopsy showed uniformity of type 1 fibers (greater than 99%) and moderate variation in fiber size without specific structural abnormality. Total external ophthalmoplegia may be one of the important clinical manifestations of CNMDU1. It is important to recognize this disorder because it is nonprogressive in nature.

A Novel Mutation of the GNE Gene in Distal Myopathy with Rimmed Vacuoles: A Case with Inflammation.

Distal myopathy with rimmed vacuoles (DMRV) is an autosomal recessive or sporadic early adult-onset myopathy caused by mutations in the UDP-N-acetylglucosamine 2-epimerase and N-acetylmannosamine kinase (GNE) gene. Characteristic pathologic features of DMRV are rimmed vacuoles on muscle biopsy and tubulofilamentous inclusion in ultrastructural study. Presence of inflammation in DMRV is unusual. We report a sporadic case of DMRV in a 40-year-old Thai man who presented with slowly progressive distal muscle weakness. Gene analysis revealed a compound heterozygous mutation of the GNE gene including a novel mutation c.1057A>G (p.K353E) and a known mutation c.2086G>A (p.V696M). The latter is the most common mutation in Thai DMRV patients. The muscle pathology was compatible with DMRV except for focal inflammation.

Diagnostic performance of advanced MRI in differentiating high-grade from low-grade gliomas in a setting of routine service.

OBJECTIVE: To evaluate the usefulness of advanced MRI techniques in differentiating high-grade (HGG) from low-grade gliomas (LGG). MATERIAL AND METHOD: Sixty-four patients with suspected gliomas were prospectively evaluated by conventional and advanced MRI studies including MR spectroscopy (MRS), diffusion tensor imagining (DTI), and dynamic susceptibility contrast (DSC) MRI. The parametric measurements of metabolic profile, cerebral blood volume, flow (CBV, CBF), apparent diffusion coefficient (ADC), fractional anisotropy, and their ratios by internal normalization were analyzed to differentiate LGG from HGG. Histopathologic findings were used as the gold standard. RESULTS: Forty-three cases with pathologically-proven gliomas were included The best discriminating features between HGG and LGG were CBV and CBF of the solid tumoral region (p < 0.05) whereas the minADC/corpus callosum ratio for DTI and the ratio of Cho/Cr for MRS of the solid tumoral region provided the best diagnostic performance (p < 0.05). With a predetermined threshold for each parametric measurement, the combination of all advanced MRI modalities was associated with the best accuracy whereas the combination of DSC MRI and MRS provided the highest specificity. When all parametric measurements were positive, the probability of HGG was 0.889. CONCLUSION: Comprehensive advanced MRI studies provided better diagnostic performance than using conventional MRI alone in the evaluation of gliomas.

Diagnostic performance of perfusion MRI in differentiating low-grade and high-grade gliomas: advanced MRI in glioma, A Siriraj project.

BACKGROUND: To determine the usefulness of the perfusion MRI technique at Siriraj Hospital for differentiating between high- and low-grade gliomas by using pathological results as the gold standard. MATERIAL AND METHOD: The authors prospectively investigated 64 consecutive patients who were suspected as cerebral glioma from prior conventional imaging. Cerebral perfusion study was achieved during the first pass of a bolus of gadolinium-based contrast agent. All post-processing MRI images were interpreted by two board-certified neuroradiologists (more than 10-year-experience), one radiology resident and one well-trained technician, who separately performed and blinded from the pathological results. RESULTS: Forty-four patients diagnosed as glioma were included in this study. There were 26 cases of high-grade and 18 cases of low-grade gliomas. The cerebral blood volume and flow and its ratios had a strong association with the grade of glioma. The areas under the ROC curve for CB K CBVratio (rCBV), CBF and CBF ratio (rCBF) are 0.778, 0.769, 0.769, and 0.772, respectively. On the basis of equal misclassification rates, a cutoff value of 6.15 for CBV (sensitivity, 81.5%; specificity, 64.7%), a cutoff value of 2.38 for the rCBV (sensitivity, 88.9%; specificity, 64.7%), a cutoff value of 0.66 for CBF (sensitivity 81.5%; specificity 70.6%), and a cutoff value of 2.6 for the rCBF (sensitivity, 85.2%; specificity, 70.60%) best discriminated the high and low-grade gliomas. CONCLUSION: Preoperative radiologic grading of gliomas based on conventional MR imaging is sometimes unreliable. The cerebral perfusion measurements can significantly improve the sensitivity and predictive values of radiologic glioma grading. The rCBV measurement is the best parameter for tumor grading due to the highest sensitivity.

Value of diffusion tensor imaging in differentiating high-grade from low-grade gliomas.

OBJECTIVE: To determine the usefulness of diffusion tensor imaging (DTI) in differentiating high-grade glioma (HGG) from low-grade glioma (LGG). MATERIAL AND METHOD: Patients with cerebral gliomas underwent conventional MRI and DTI before surgery. All proven pathologies were classified into two groups, i.e. LGG and HGG. The authors measured fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values in region of interest (ROI) including solid tumoral region, necrotic region, peritumoral edema, contralateral normal appearing white matter (NAWM) and normal corpus callosum as well as calculated ADC ratios. Pairwise comparisons were performed by using the t-test. The ROC curves of imaging parameters were employed to determine the best parameter for differentiating the two entities. RESULTS: Forty-three patients with cerebral gliomas, 17 with LGG and 26 with HGG, no statistical significant difference between LGG and HGG using mean FA values in each ROI. The ADC and minimal ADC values of solid tumoral region and peritumoral edema, the ADC and minimal ADC ratios of solid tumoral region are statistical significant to differentiate HGG from LGG, p < 0.05. The ratio ADC solid tumoral region to normal corpus callosum had highest predictive accuracy to differentiate the two entities with AUC of 0.74. CONCLUSION: The ADC value, minimal ADC value, and ADC ratios of solid tumoral region appeared to be useful for differentiating HGG from LGG.

Severe plexiform facial neurofibromatosis, type 1 with underdeveloped eyes and a novel NF1 mutation.

A Thai woman, who was affected with neurofibromatosis type 1, was followed up and re-evaluated at ages 45, 61, and 67 years. Her mother and her three brothers were also affected. The proposita was very severely affected. She was born blind with underdeveloped eyeglobes and had large plexiform neurofibromas on her face. Her eyelids were gigantic and tears drained from the orifice between them. Cutaneous neurofibromas were observed all over her body. A novel mutation c.4821delA was identified in NF1 gene, which predicted truncation of neurofibromin (p.Leu1607fs).

Glutaric aciduria type 2, late onset type in Thai siblings with myopathy.

Reported here is a novel presentation of late onset glutaric aciduria type 2 in two Thai siblings. A 9-year-old boy presented with gradual onset of proximal muscle weakness for 6 weeks. The initial diagnosis was postviral myositis, and then polymyositis. Electromyography and nerve conduction velocity testing indicated a myopathic pattern. Muscle biopsy revealed excessive accumulation of fat. Acylcarnitine profiling led to the diagnosis of glutaric aciduria type 2. Immunoblot analysis of electron-transferring-flavoprotein and its dehydrogenase electron-transferring-flavoprotein dehydrogenase led to mutation analysis of the ETFDH gene, which revealed two different pathogenic mutations in both alleles and confirmed the diagnosis of glutaric aciduria type 2 caused by electron-transferring-flavoprotein dehydrogenase deficiency. The boy recovered completely after treatment. Later, his younger sibling became symptomatic; the same diagnosis was confirmed, and treatment was similarly effective. Acylcarnitine profiling was a crucial investigation in making this diagnosis in the presence of normal urine organic acid findings. Late onset glutaric aciduria type 2, a rare cause of muscle weakness in children, should be included in the differential diagnosis of myopathy.

Primary muscle diseases in Thammasat University Hospital: muscle biopsy study of 12 cases.

We reviewed retrospectively 12 muscle biopsies of patients who were clinically diagnosed with a primary muscle diseases from the clinical data base of Thammasat University Hospital from January 2005 to January 2007. Most patients were male and had median age of 30.5 years (range 14 to 56). The most common clinical presentation was proximal muscle weakness. Nine of eleven patients had elevated CK concentrations ranging from 338 to 1023 IU/L. Clinicopathological correlation revealed specific diagnoses in nine patients. Suspected cases of mitochondrial neurogastrointestinal encephalopathy (MNGIE), myofibrillar myopathy (MFM) and distal myopathy with rimmed vacuoles (DMRV) were confirmed by molecular genetic studies examining thymidine phosphorylase, GNE, ZASP myotilin, desmin, abeta-crystalline and filamin C genes. Specific histopathological findings on muscle biopsy help to select cases for advance molecular testing.

Novel DYSF mutations in Thai patients with distal myopathy.

Dysferlinopathy refers to a variety of autosomal recessive, skeletal muscle disorders due to the mutations of dysferlin-encoding gene, DYSF. It encompasses limb-girdle muscular dystrophy type 2B (LGMD2B), Miyoshi myopathy (MM), distal myopathy with anterior tibial onset (DMAT), isolated hyperCKemia, rigid spine syndrome and congenital muscular dystrophy. Herein, we report five Thai patients with distal myopathy due to dysferlinopathy including four MM and one DMAT patients. Muscle biopsy from one MM patient depicted numerous ring fibers which is an atypical finding in dysferlinopathy. Mutation analysis of DYSF revealed novel compound heterozygous mutations of p.Tyr309X and c.236+1G>T in two related MM patients, known homozygous mutations, p.Arg89X and p.Gln176X, in two MM patients and a heterozygous missense mutation, p.Arg555Trp, in a DMAT patient. Most of the previously reported DMAT patients were Hispanic. To the best of our knowledge, this is the first report of genetically confirmed patients with dysferlinopathy in Thailand.

Diagnostic accuracy of perfusion CT in differentiating brain abscess from necrotic tumor.

OBJECTIVE: To evaluate the diagnostic accuracy of perfusion computed tomography (CTP) in differentiating between brain abscess and necrotic tumor. MATERIAL AND METHOD: Prospective study was performed in patients suspected of a space taking lesion in the brain. CTP was done at the suspected levels and post-processing measurement of cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time (MTT), and permeability surface index (PS) were evaluated at ring enhanced area, central non-enhanced area, edema and contralateral normal brain. RESULTS: Seventeen patients with 21 lesions were studied. Of the 21 lesions, 12 were abscess and nine were tumors. By comparing means, only MTT at the ring enhanced area showed statistically significant difference between brain abscess and tumor (p = 0.009, 95% CI = 1.403 to 4.900). When ratio of CBV, CBF and MTT of the ring enhanced area and contralateral normal brain were analyzed (CBVr, CBFr, MTTr respectively), there were significant differences of CBVr and CBFr between the two groups (p = 0.003, 95% CI = -4.266 to -1.051 and p = 0.006, 95% CI = -9.934 to -1.969 respectively). With the threshold of CBVr more than or equal to 1.5 and CBFr more than or equal to 1, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for diagnosis of tumor were 100%, 75%, 75%, 100%, and 85.7% respectively. CONCLUSION: The CTP was shown to be useful in differentiating brain abscess from tumor. With CBVr less than 1.5, tumor can be excluded.

Myofibrillar myopathy with limb-girdle phenotype in a Thai patient.

Myofibrillar myopathy (MFM) encompasses a genetically and clinically heterogeneous group of inherited or sporadic skeletal muscle disorders characterized pathologically by the presence of myofibrillar dissolution associated with accumulation of myofibrillar degradation products and ectopic expression of multiple proteins especially Z-disk related proteins. Patients with MFM initially present with muscle weakness and commonly developed cardiomypathy in the advanced stage. To date, mutations of genes encoding Z-disk proteins or proteins maintaining myofibrillar integrity including ZASP, MYOT, DES, FLNC and CRYAB underlie MFM. The authors herein report a 29-year-old Thai woman with a clinical diagnosis of autosomal dominant limb-girdle muscular dystrophy (LGMD1) who has one affected grandmother. The patient was subsequently found to have MFM based on her myopathological findings. Analyses of all MFM-genes known to date revealed no mutations. The current case emphasizes the importance of muscle biopsy in LGMD1 patients and a wide range of phenotypic variations among patients with MFM. The causative genes underlying the majority of MFM remain uncovered. Close monitoring of the cardiac function is crucial to prevent mortality among these patients.

Evaluation of an in-house immunoperoxidase staining assay for histodiagnosis of human pythiosis.

Pythiosis, a life-threatening infectious disease of humans and animals in tropical and subtropical countries, is caused by the fungus-like organism Pythium insidiosum. As diagnosis of pythiosis is difficult, delayed diagnosis of pythiosis leads to poor prognosis. We developed an immunoperoxidase staining assay using rabbit anti-P. insidiosum antibodies to detect P. insidiosum directly in infected tissues of 19 patients with vascular (n = 11), ocular (n = 7) or cutaneous (n = 1) pythiosis. Tissue sections from 31 patients with various fungal infections were included as controls. Tissue sections from all pythiosis patients and 2 patients with Fusarium infections were stained positive, whereas the other 29 control sections were stained negative. Sensitivity and specificity of the assay was 100% and 94%, respectively. Based on the prevalence of human pythiosis (2%), calculated positive predictive value and negative predictive value was 24% and 100%, respectively. Thus, the diagnostic value of this assay is for ruling out pythiosis. The assay requires routine laboratory equipments and can easily be performed by pathologists in rural hospitals where the disease is more prevalent.