Uniprot Description A form of arthrogryposis multiplex congenita, a developmental condition characterized by multiple joint contractures resulting from reduced or absent fetal movements. AMCNMY is an autosomal recessive severe form with onset in utero. Most affected individuals die in utero. Those who survive have generalized contractures and hypotonia. The disorder is caused by a neurogenic defect and poor or absent myelin formation around peripheral nerves rather than by a muscular defect.