Neonatal arthrogryposis and absent limb muscles: a muscle developmental gene defect?

We describe a child who presented at birth with arthrogryposis. Following a muscle biopsy a diagnosis of congenital muscular dystrophy was made and a skin biopsy 12 years later confirmed the presence of merosin. Her clinical picture was unusual, however, for merosin-positive congenital muscular dyst rophy. She had extreme wasting and weakness of her arms and legs. In contra st, she had good neck and trunk control, and no facial or respiratory muscl e weakness. We have used magnetic resonance imaging to examine the pattern of muscle involvement in this case. No recognizable muscle could be identif ied in the limbs. In contrast, the axial muscles were preserved. This strik ing pattern of virtual absence of muscles in the limbs with sparing of the axial muscle suggests that a gene responsible for the migration and/or prol iferation of limb muscle precursor cells may be involved in the disease pro cess. It is recognized that merosin-positive congenital muscular dystrophy is a heterogeneous disease. Magnetic resonance imaging is a useful tool for examining in detail the pattern of muscle involvement and identifying indi vidual phenotypes, Understanding more about which muscles are affected in c hildren with congenital myopathies may provide information on the underlyin g pathological process and help in the search for candidate proteins and ge nes. (C) 2001 Elsevier Science B.V. All rights reserved.