학술논문
A Heterozygous Mutation in the Filamin C Gene Causes an Unusual Nemaline Myopathy With Ring Fibers
ORIGINAL ARTICLE
ORIGINAL ARTICLE
Document Type
Report
Author
Source
Journal of Neuropathology and Experimental Neurology. August 2020, Vol. 79 Issue 8, p908, 7 p.
Subject
Language
English
ISSN
0022-3069
Abstract
INTRODUCTION Filamin C (FLNC)-related myopathies are autosomal dominant conditions caused by pathogenic variants in FLNC. FLNC pathogenic variants are most often associated with myofibrillar myopathy (MFM) or cardiomyopathies. However, forms [...]
Autosomal dominant pathogenic variants in the filamin C gene (FLNC) have been associated with myofibrillar myopathies, distal myopathies, and isolated cardiomyopathies. Mutations in different functional domains of FLNC can cause various clinical phenotypes. A novel heterozygous missense variant c.608G>A, p.(Cys203Tyr) in the actin binding domain of FLCN was found to cause an upper limb distal myopathy (MIM #614065). The muscle MRI findings are similar to those observed in FLNC-myofibrillar myopathy (MiM #609524). However, the muscle biopsy revealed >20% of muscle fibers with nemaline bodies, in addition to numerous ring fibers and a predominance of type 1 fibers. Overall, this case shows some unique and rare aspects of FLNC-myopathy constituting a new morphologic phenotype of FLNC-related myopathies. Key Words: Filamin C (FLNC), Filamin C-related myopathies, Muscle MRI, Nemaline bodies, Sarcomere disorganization.
Autosomal dominant pathogenic variants in the filamin C gene (FLNC) have been associated with myofibrillar myopathies, distal myopathies, and isolated cardiomyopathies. Mutations in different functional domains of FLNC can cause various clinical phenotypes. A novel heterozygous missense variant c.608G>A, p.(Cys203Tyr) in the actin binding domain of FLCN was found to cause an upper limb distal myopathy (MIM #614065). The muscle MRI findings are similar to those observed in FLNC-myofibrillar myopathy (MiM #609524). However, the muscle biopsy revealed >20% of muscle fibers with nemaline bodies, in addition to numerous ring fibers and a predominance of type 1 fibers. Overall, this case shows some unique and rare aspects of FLNC-myopathy constituting a new morphologic phenotype of FLNC-related myopathies. Key Words: Filamin C (FLNC), Filamin C-related myopathies, Muscle MRI, Nemaline bodies, Sarcomere disorganization.