CANOMAD and other chronic ataxic neuropathies with disialosyl antibodies (CANDA).

INTRODUCTION: CANOMAD/CANDA are syndromes characterized by ataxic neuropathy, ophthalmoplegia, monoclonal gammopathy, cold agglutinins and disialosyl antibodies. METHODS: A retrospective review of our neuromuscular autoantibody panel database was performed. Anti-GD1b seropositive patients with ataxia were included. RESULTS: Eleven patients were identified. Median age at onset was 56 years. Median disease duration was 6 years. All patients had gait disorders. Nine had ocular motility abnormalities. Most had a monoclonal protein and all had elevated serum IgM. Electrodiagnostic studies showed a mixed axonal/demyelinating pattern (6), an axonal pattern (4), or a pure demyelinating pattern (1). Ultrasounds showed nerve enlargement patterns consistent with acquired demyelination. A nerve biopsy showed near complete loss of myelinated axons with preservation of smaller axons. Rituximab was the most effective immunotherapy. CONCLUSION: CANOMAD/CANDA are rare and debilitating disorders with characteristic clinical and diagnostic findings. In our cohort, nerve ultrasound showed regional nerve enlargement and rituximab was the most effective immunomodulatory therapy.

Diagnosis and management of adult hereditary cardio-neuromuscular disorders: A model for the multidisciplinary care of complex genetic disorders.

Genetic disorders that disrupt the structure and function of the cardiovascular system and the peripheral nervous system are common enough to be encountered in routine cardiovascular practice. Although often these patients are diagnosed in childhood and come to the cardiologist fully characterized, some patients with hereditary neuromuscular disease may not manifest until adulthood and will present initially to the adult cardiologist for an evaluation of an abnormal ECG, unexplained syncope, LV hypertrophy, and or a dilated cardiomyopathy of unknown cause. Cardiologists are often ill-equipped to manage these patients due to lack of training and exposure as well as the complete absence of practice guidelines to aid in the diagnosis and management of these disorders. Here, we review three key neuromuscular diseases that affect the cardiovascular system in adults (myotonic dystrophy type 1, Friedreich ataxia, and Emery-Dreifuss muscular dystrophy), with an emphasis on their clinical presentation, genetic and molecular pathogenesis, and recent important research on medical and interventional treatments. We also advocate the development of interdisciplinary cardio-neuromuscular clinics to optimize the care for these patients.

Coenzyme Q10 deficiency in children: frequent type 2C muscle fibers with normal morphology.

INTRODUCTION: Neurological disorders with low tissue coenzyme Q10 (CoQ10) levels are important to identify, as they may be treatable. METHODS: We evaluated retrospectively clinical, laboratory, and muscle histochemistry and oxidative enzyme characteristics in 49 children with suspected mitochondrial disorders. We compared 18 with CoQ10 deficiency in muscle to 31 with normal CoQ10 values. RESULTS: Muscle from CoQ10-deficient patients averaged 5.5-fold more frequent type 2C muscle fibers than controls (P < 0.0001). A type 2C fiber frequency of ≥ 5% had 89% sensitivity and 84% specificity for CoQ10 deficiency in this cohort. No biopsy showed active myopathy. There were no differences between groups in frequencies of mitochondrial myopathologic, clinical, or laboratory features. Multiple abnormalities in muscle oxidative enzyme activities were more frequent in CoQ10-deficient patients than in controls. CONCLUSIONS: When a childhood mitochondrial disorder is suspected, an increased frequency of type 2C fibers in morphologically normal muscle suggests CoQ10 deficiency.

Multifocal radiculoneuropathy during ipilimumab treatment of melanoma.

INTRODUCTION: Ipilimumab, a monoclonal anti-CTLA-4 antibody, is used to treat melanoma. Neuromuscular side effects, possibly autoimmune, may occur. METHODS: In this investigation we undertook a retrospective review of patient records. RESULTS: After 3 doses of ipilimumab, a 31-year-old man developed asymmetric, severe weakness involving all limbs, respiration, and cranial nerves, which was progressive over 2 weeks. EMG/NCS showed an axonal polyradiculoneuropathy with multifocal motor conduction blocks. CSF protein was 749 mg/dl. Nerve pathology showed inflammation around the endoneurial microvessels and subperineurial edema and inflammation. Spine MRI showed leptomeningeal and anterior and posterior root enhancement. Strength improved slowly over months after ipilimumab discontinuation and immunomodulating treatment. CONCLUSIONS: Ipilimumab toxicity presented as a monophasic, multifocal, asymmetric polyradiculoneuropathy involving roots and peripheral and cranial nerves. Ipilimumab may produce a polyradiculoneuropathy with disruption of the blood-nerve barrier due to a microvasculopathy.

Clinical and laboratory features of neuropathies with serum IgM binding to TS-HDS.

INTRODUCTION: In this investigation we studied clinical and laboratory features of polyneuropathies in patients with serum IgM binding to the trisulfated disaccharide IdoA2S-GlcNS-6S (TS-HDS). METHODS: We retrospectively compared 58 patients with selective IgM binding to TS-HDS to 41 consecutive patients with polyneuropathies without TS-HDS binding. RESULTS: Patients with IgM vs. TS-HDS commonly had distal, sensory, axonal neuropathies. Weakness was associated with IgM M-proteins. Hand pain and serum IgM M-proteins were more common than in control neuropathy patients. TS-HDS antibody binding was often selectively κ class. Biopsies showed capillary pathology with thickened basal lamina and C5b9 complement deposition. IgM in sera with TS-HDS antibodies often bound to capillaries. CONCLUSIONS: Serum IgM binding to TS-HDS is associated with painful, sensory > motor, polyneuropathies with an increased frequency of persistent hand discomfort, serum IgM M-proteins, and capillary pathology. Serum IgM binding to TS-HDS suggests a possible immune etiology underlying some otherwise idiopathic sensory polyneuropathies.

Exome sequencing reveals DNAJB6 mutations in dominantly-inherited myopathy.

OBJECTIVE: To identify the causative gene in an autosomal dominant limb-girdle muscular dystrophy (LGMD) with skeletal muscle vacuoles. METHODS: Exome sequencing was used to identify candidate mutations in the studied pedigree. Genome-wide linkage was then used to narrow the list of candidates to a single disease-associated mutation. Additional pedigrees with dominant or sporadic myopathy were screened for mutations in the same gene (DNAJB6) using exome sequencing. Skeletal muscle from affected patients was evaluated with histochemistry and immunohistochemical stains for dystrophy-related proteins, SMI-31, TDP43, and DNAJB6. RESULTS: Exome analysis in 3 affected individuals from a family with dominant LGMD and vacuolar pathology identified novel candidate mutations in 22 genes. Linkage analysis excluded all variants except a Phe93Leu mutation in the G/F domain of the DNAJB6 gene, which resides within the LGMD locus at 7q36. Analysis of exome sequencing data from other pedigrees with dominant myopathy identified a second G/F domain mutation (Pro96Arg) in DNAJB6. Affected muscle showed mild dystrophic changes, vacuoles, and abnormal aggregation of proteins, including TDP-43 and DNAJB6 itself. INTERPRETATION: Mutations within the G/F domain of DNAJB6 are a novel cause of dominantly-inherited myopathy. DNAJB6 is a member of the HSP40/DNAJ family of molecular co-chaperones tasked with protecting client proteins from irreversible aggregation during protein synthesis or during times of cellular stress. The abnormal accumulation of several proteins in patient muscle, including DNAJB6 itself, suggest that DNAJB6 function is compromised by the identified G/F domain mutations.

Eosinophilic vasculitis in an isolated central nervous system distribution.

Eosinophilic vasculitis has been described as part of the Churg-Strauss syndrome, but affects the central nervous system (CNS) in <10% of cases. A 39-year-old woman with a history of migraine without aura presented to an institution in an acute confusional state with concurrent headache and left-sided weakness. Laboratory evaluation showed an increased cerebrospinal fluid (CSF) protein level, but otherwise unremarkable serologies. Magnetic resonance imaging showed bifrontal polar gyral-enhancing brain lesions. Her symptoms resolved over two weeks without residual deficits. Eighteen months later the patient presented with similar symptoms and neuroradiological findings showed involvement of territories different from those in her first episode. Brain biopsy showed transmural, predominantly eosinophilic, inflammatory infiltrates and fibrinoid necrosis without granulomas. She improved when treated with corticosteroids. To our knowledge, this is the first case of non-granulomatous eosinophilic vasculitis isolated to the CNS. No aetiology for this patient's primary CNS eosinophilic vasculitis has yet been identified.