FAMILIAL FETAL AKINESIA DEFORMATION SEQUENCE WITH A SKELETAL-MUSCLE MATURATION DEFECT

Two female siblings with the fetal akinesia deformation sequence (FADS ) are described. Both showed facial anomalies, arthrogrypotic extremit ies, hypoplastic lungs, and fetal growth retardation. The central nerv ous system of the second sibling, including the spinal cord, was norma l. The skeletal muscle was studied by immunohistochemistry for the exp ression of several myosin heavy chain isoforms, M-band proteins and in termediate filament proteins. The skeletal muscle was immature and aty pical muscle spindles containing up to 31 intrafusal fibers were found . These findings suggest that a lethal FADS phenotype may involve a ma turation defect of the skeletal muscle, and, in this family, may be in herited in a recessive fashion.