Lahoria, Rajat

ABSTRACTIntroduction: Voltage‐gated Kv1 potassium channel complex (VGKC) autoantibodies subtyped for leucine‐rich glioma‐inactivated 1 (LGI1), contactin‐associated‐proteinlike 2 (CASPR2), and Kv IgGs have a spectrum of neurological presentations. Painful polyneuropathy is seen in some patients, but nerve pathology descriptions are lacking. Methods: Clinicopathologic features were studied in subtyped VGKC‐autoantibody‐seropositive patients who had undergone nerve biopsies. Results: Five patients were identified, 1 LGI1 IgG positive and 1 CASPR2 IgG positive, but all negative for Kv1.1‐, 1.2‐, 1.6‐subtyped IgG autoantibodies. Median symptom duration was 17 months. Pain was the predominant symptom; 3 had mild sensory loss and/or weakness. Histopathological abnormalities were limited to axonal loss in 3. None had mononuclear cellular infiltrates. Electron micrographs revealed no interstitial abnormalities. Three patients reported marked improvement in pain with immunotherapy. Conclusions: The nerve biopsy histopathology of patients subtyped for LGI1 and CASPR2 IgGs within the VGKC‐complex spectrum disorders shows either normal density or axonal fiber loss without inflammatory infiltrates. A reversible neural hyperexcitable mechanism is considered to be the cause of this painful polyneuropathy. Muscle Nerve 55: 520–525, 2017

ABSTRACTIntroductionNeurolymphomatosis (NL) is a rare disorder characterized by invasion of cranial or peripheral nerves, nerve roots, or plexi, usually by aggressive subtypes of non‐Hodgkin lymphoma (NHL). The most common clinical presentation is that of a painful polyneuropathy or polyradiculopathy, followed by cranial neuropathy and, less frequently, by painless polyneuropathy.MethodsClinical and pathologic findings are reported for 2 NL cases.ResultsThe following 2 patients with NL, with disparate clinical presentations, are presented: a patient with subacute onset, painful, multifocal, mixed axonal and demyelinating radiculoplexus neuropathy due to a large B‐cell NHL, who required 2 targeted fascicular nerve biopsies to demonstrate NL; and a patient with a slowly progressive, length‐dependent axonal polyneuropathy due to a low‐grade B‐cell lymphoproliferative disorder, as shown on a diagnostic sural nerve biopsy.ConclusionsThe cases described illustrate the wide clinical spectrum of NL. Muscle Nerve 52:449–454, 2015

ABSTRACTIntroduction: Recessive mutations in the anoctamin‐5 gene (ANO5) cause a spectrum of clinical phenotypes, including limb‐girdle muscular dystrophy (LGMD 2L), distal myopathy, and asymptomatic hyperCKemia. Methods: In this report we describe our clinical, electrophysiological, pathological, and molecular findings in a subject with anoctaminopathy‐5. Results: A 49‐year‐old Arabic man from a consanguineous family presented with a 5‐year history of myalgias, hyperCKemia and an episode of unprovoked rhabdomyolysis. Muscle biopsy showed mild myopathic changes and interstitial amyloid deposition. ANO5 analysis detected a novel homozygous deletion of approximately 11.9 kb encompassing exons 13–17, predicted to be pathogenic. Conclusions: Anoctaminopathy‐5 can manifest with a phenotype reminiscent of metabolic myopathy and should be considered as a potential cause of myalgia and myoglobinuria. Amyloid deposition in the muscle biopsy is helpful for the diagnosis. A novel homozygous ANO5 deletion was identified, suggesting that screening for common mutations may have low yield in non‐European subjects. Muscle Nerve 50: 610–613, 2014