Clinical Features and Genotypes of Laing Distal Myopathy in a Group of Chinese Patients, With In-Frame Deletions of MYH7 as Common Mutations

Abstract

<jats:title>Abstract</jats:title> <jats:p><jats:bold>Background</jats:bold>: Laing distal myopathy is a rare autosomal dominant inherited distal myopathy caused by mutations of the <jats:italic>MYH7</jats:italic> gene affecting mainly the rod region. We described the clinical features, muscle MRI and pathological changes as well as genetic mutations in a group of Chinese patients of Laing distal myopathy. <jats:bold>Results</jats:bold>: Six patients with the confirmed diagnoses of Laing distal myopathy were recruited. Ankle dorsiflexion and finger extension weakness were common in our patients as well as neck flexion weakness. Myopathic as well as neurogenic lesions were suggested by electromyography in different patients. Respiratory abnormality of sleep apnea was detected in two of our patients stressing the necessity of close respiratory monitoring in this disease. Muscle MRIs showed similar features of concentric fatty infiltration of anterior thigh muscles together with early involvement of tibialis anterior and extensor hallucis longus. However, muscle pathological presentations were varied depending on the biopsied muscles and severity of the disease. In-frame deletions of the <jats:italic>MYH7</jats:italic> gene made up 3/4 of mutations in our patients, suggesting these are common mutations of Laing distal myopathy. <jats:bold>Conclusions</jats:bold>: Our study further expanded the phenotypes and genotypes of Laing distal myopathy. In-frame deletions of <jats:italic>MYH7</jats:italic> gene are common causes of Laing distal myopathy.</jats:p>