| Keywords [eng] |
MYH2(Myosin Heavy Chain II), Ophthalmoplegia, Ptosis, Muscle weakness, Contractures at birth, Creatine Kinase, Muscle biopsy, Rehabilitation |
| Abstract [eng] |
This study endeavors to scrutinize Myosin Heavy Chain II-related disorders across pediatric and adult populations, delineating their clinical manifestations, diagnostic hallmarks, genetic underpinnings, and prognostic implications. Through a comprehensive literature review, a selection of scholarly articles sourced from PubMed has been curated, shedding light on the spectrum of disease severity and progression in genetically confirmed Myosin Heavy Chain II-afflicted individuals. Myosinopathies, a constellation of exceedingly rare inherited muscular afflictions, exhibit diverse phenotypic characteristics attributable to variants occurring within the myosin heavy chain genes located on chromosome 17. Among these, Myosin Heavy Chain II, a critical isoform predominantly expressed in fast twitch 2A and 2B muscle fibers, manifests with distinct clinical phenotypes. Autosomal Dominant Myosin Heavy Chain II myopathy typically manifests as transient congenital arthrogryposis, succeeded by the insidious onset of progressive proximal limb weakness and external ophthalmoplegia. Notably, characteristic histological findings on muscle biopsy often include diminished type 2A fibers and the presence of rimmed vacuoles. Conversely, Autosomal Recessive Myosin Heavy Chain II myopathy presents with a milder, early-onset, non-progressive proximo-distal weakness of the limbs accompanied by external ophthalmoparesis. Histopathological analyses typically reveal a stark absence of type 2A fibers alongside non-specific myopathic alterations. The diagnosis and management of myopathy pose formidable challenges for clinicians, notwithstanding recent strides in molecular biology that have facilitated swifter and more precise diagnostic paradigms for genetically or metabolically mediated myopathies. Nonetheless, efficacious therapeutic modalities remain elusive. While gene therapy and stem cell transplantation exhibit promising potential in the realm of myopathy research, concerns regarding the safety profile of adeno-associated virus vectors and the potential for stem cell-associated tumorigenicity have curtailed their widespread clinical implementation. Presently, rehabilitation therapy stands as the cornerstone of myopathy management, underscoring the critical need for further research endeavors aimed at unraveling the intricate pathophysiological mechanisms underlying Myosin Heavy Chain II-related disorders and identifying novel therapeutic avenues to ameliorate disease burden and enhance patient outcomes. |
