Congenital myopathy associated with abnormal accumulation of desmin and dystrophin

We studied a 5-yr-old boy clinically presenting congenital myopathy. Muscle biopsy showed sarcoplasmic accumulation of desmin filaments leading to diagnosis of desmin storage myopathy. An immunohistochemical study of other cytoskeletal proteins (actin, alpha-actinin, vimentin and dystrophin) was performed. Desmin positive areas reacted strongly with anti-midrod and C-terminus dystrophin antibodies. Probed with the same antibodies by Western blot, desmin and dystrophin showed normal molecular size but densitometric analysis demonstrated a parallel increase of both proteins. Our results indicate that intrasarcoplasmic desmin storage is associated with an abnormal accumulation of dystrophin. Since no other cytoskeletal proteins are accumulated this finding seems to be specific and suggests a possible structural and functional association between these two proteins in striated muscle.