Novel LMNA Mutation Presenting as Severe Congenital Muscular Dystrophy

Abstract

Mutations in the lamin A/C gene determine a heterogeneous group of congenital diseases, termed laminopathies, consisting of more than 15 phenotypes, including autosomal dominant Emery-Dreifuss muscular dystrophy and limb-girdle muscular dystrophy type 1B. Early onset in infancy has been described in these muscular dystrophies. Reported here is a 7-year-old male with congenital muscular dystrophy. Remarkably, muscle weakness and wasting affected predominantly axial muscles as well as proximal upper and distal lower extremities. The patient rapidly developed joint contractures and spine rigidity with the head only mildly flexed. Serum creatine kinase was moderately elevated. Muscle biopsy indicated a dystrophic pattern with normal immunochemical findings. A novel, de novo missense substitution p.Asn39Tyr within the lamin A/C gene confirmed the diagnosis of a laminopathy. This report broadens the spectrum of lamin A/C gene mutations and illustrates the phenotypic variability of laminopathies with early onset congenital muscular dystrophy. Mutations in the lamin A/C gene should be sought in any infant with dystrophic features and normal tissue immunochemical studies; especially in the presence of moderately elevated serum creatine kinase, predominant axial and humeroperoneal weakness, spine rigidity, and joint contractures.