An infant with arthrogryposis multiplex and other malformations born to a mother who presented with myasthenia gravis immediately following cesarean section is reported from the Depts Neonatology and Obstetrics, Hasharon Hospital, Petah-Tiqva, Tel Aviv Univ Med Sch, Israel. The baby had hypotonia, absent suck, weak cry, and incomplete Moro. Multiple malformations included craniofacial dysmorphism, kyphoscoliosis, eventration of the diaphragm, and flexion contractures of the limbs. A Tensilon test at 7 days was negative and treatment with Mestinon for 3 weeks was without benefit, the infant dying at 5 weeks of age. Cytogenetic studies on infant and mother were normal. The authors suggest that the failure to recognize and treat the myasthenia gravis during pregnancy may be causally related to the infant’s multiple malformations and fatal outcome. 
COMMENT. Electromyography and nerve conduction studies, muscle biopsy and serum CPK may assist in determination of the site and nature of the pathology in cases of arthrogryposis. These tests were apparently not performed in the present case and the underlying cause of the hypotonia was not defined, except to rule out a transient neonatal form of myasthenia. A fetal form of spinal muscular atrophy, as described originally by Beevor CE  and later by Brandt S , in association with arthrogryposis multiplex congenita, seems a more likely explanation for the fatal outcome than the maternal myasthenia.