Identification of novel FHL1 mutations associated with X-linked scapuloperoneal myopathy in unrelated Chinese patients

Abstract

Mutations in the FHL1 gene can be associated with a variety of X-linked myopathies and cardiomyopathies, among which X-linked dominant scapuloperoneal myopathy is a rare phenotype. We collected the clinical data of two unrelated Chinese patients with X-linked scapuloperoneal myopathy and analyzed their clinical, pathological, muscle imaging, and genetic features. Both patients were characterized by scapular winging, bilateral Achilles tendon contractures, and weakness in shoulder-girdle and peroneal muscles. Muscle biopsy revealed myopathic changes, and no reducing bodies were found. Muscle magnetic resonance imaging was dominated by fatty infiltration, with minor edema-like findings. Genetic analysis revealed two novel mutations in the FHL1 gene: c.380T > C (p.F127S) and c.802C > T (p.Q268*), which were located in the LIM2 domain and the C-terminal sequence, respectively. To our knowledge, this is the first report of X-linked scapuloperoneal myopathy in the Chinese population. Our findings broadened the genetic and ethnic spectrum of FHL1-related disorders and proposed to look for variants in the FHL1 gene when scapuloperoneal myopathy is observed in the clinical work.