A Novel MYH14 Variant Presenting as a New Phenotype of MYH14-Associated Neuromuscular Disorders-Clinicohistologic Findings and Review of the Literature.

Background: Pathogenic variants in the nonmuscle myosin, MYH14, have been associated with several pathologic conditions including a complex phenotype with peripheral neuropathy, myopathy, hoarseness, and hearing loss. Since its first description in a large Korean kindred, this rare neuromuscular disorder has further been characterized in 1 American and 1 Canadian pedigree.

Case Presentation: Here, we describe a German patient with atypical MYH14-related neuromuscular disorder.

A stagewise response to mitochondrial dysfunction in mitochondrial DNA maintenance disorders.

Mitochondrial DNA (mtDNA) deletions which clonally expand in skeletal muscle of patients with mtDNA maintenance disorders, impair mitochondrial oxidative phosphorylation dysfunction. Previously we have shown that these mtDNA deletions arise and accumulate in perinuclear mitochondria causing localised mitochondrial dysfunction before spreading through the muscle fibre. We believe that mito-nuclear signalling is a key contributor in the accumulation and spread of mtDNA deletions, and that knowledge of how muscle fibres respond to mitochondrial dysfunction is key to our understanding of disease mechanisms.

Quantitative whole-body muscle MRI in idiopathic inflammatory myopathies including polymyositis with mitochondrial pathology: indications for a disease spectrum.

Objective: Inflammatory myopathies (IIM) include dermatomyositis (DM), sporadic inclusion body myositis (sIBM), immune-mediated necrotizing myopathy (IMNM), and overlap myositis (OLM)/antisynthetase syndrome (ASyS). There is also a rare variant termed polymyositis with mitochondrial pathology (PM-Mito), which is considered a sIBM precursor. There is no information regarding muscle MRI for this rare entity.

Skeletal muscle fibers produce B-cell stimulatory factors in chronic myositis.

Introduction: We aimed to identify B-cell-mediated immunomechanisms in inclusion body myositis (IBM) and polymyositis (PM) as part of the complex pathophysiology.

Materials And Methods: Human primary myotube cultures were derived from orthopedic surgery. Diagnostic biopsy specimens from patients with IBM (n=9) and PM (n=9) were analyzed for markers of B cell activation (BAFF and APRIL) and for chemokines that control the recruitment of B cells (CXCL-12 and CXCL-13).

Personality factors in patients with myasthenia gravis: A prospective study.

Introduction: In myasthenia gravis (MG), depression and anxiety have frequently been reported as comorbidities. However, little is known about personality characteristics in MG patients. We aimed to characterise personality traits in MG and to correlate them with disease severity and disease course.