A case of severe neurogenic arthrogryposis multiplex congenita caused by absence of peripheral nerve myelin in an infant who died at age 31 days of aspiration pneumonia is described from the Dept of Neurology, Neuromuscular Division, Johns Hopkins University School of Medicine, Baltimore, MD. The infant, delivered by Cesarean section, had Apgar scores of one at 1 and 5 minutes, and examination revealed multiple fixed joints, small chin and triangular face, bilateral extraocular and facial pareses, diffuse hypotonia, muscle atrophy, and areflexia. Absence of myelin in the peripheral nerves at autopsy reflected an arrest in the differentiation or maturation of Schwann cells at the stages of elongation and longitudinal growth of the mesaxon. The authors refer to serial ultrasonography to assess fetal movement after the 18th week, the time of onset of peripheral nerve myelination, as an antenatal diagnostic technique in such families, and as suggested by Miskin M et al. 
COMMENT. The most common cause of arthrogryposis multiplex congenita is probably an amyoplasia due to anterior horn cell maldevelopment and associated muscle atrophy. Other causes include anterior horn cell degeneration, congenital myopathies, mechanical interference with fetal movement, and peripheral neuropathy. Paralysis of fetal movement is the common link in all forms of the disorder. For a comprehensive account of arthrogryposis, the reader should refer to Clinical Orthopedics April 1985;194, an issue devoted entirely to the topic. A long-term follow-up study showed that 17 of 34 patients examined at 16 years of age or older were able to walk independently and 9 others walked with the aid of crutches or braces. The prognosis is obviously hopeful in a majority of cases with nonprogressive underlying causes, and appropriate orthopedic procedures can achieve correction and relative independence at an early age.