Phenotypic expression of a novel desmin gene mutation: hypertrophic cardiomyopathy followed by systemic myopathy.

Hypertrophic cardiomyopathy is a heterogeneous disease caused by gene mutations. Most of the disease-causing mutations were found in the genes for sarcomeric proteins, but there are several cases carrying mutations in genes for extra-sarcomeric cytoskeletons. Desmin is a member of extra-sarcomeric cytoskeletons and plays an important role in muscle contraction. Mutations in the desmin gene cause various type of general myopathy and/or cardiomyopathy, known as desmin-related myopathies. We identified a novel desmin missense mutation, Thr219Pro, in the homozygous state in a patient, who first manifested with hypertrophic cardiomyopathy and later progressed to general myopathy. His parents were heterozygous for the mutation, but showed no clinical abnormality, suggesting the recessive inheritance of the mutation. We here report a severe phenotype of hypertrophic cardiomyopathy preceded the onset of general myopathy caused by a novel homozygous missense mutation in the 1B α-helix domain of desmin.