Fetal akinesia-hypokinesia deformation sequence (FADS) in 2 siblings with congenital myotonic dystrophy

Two premature siblings described herein had clinical features comparable to the fetal akinesia-hypokinesia deformation sequence (Pena-Shokeir syndrome) with polyhydramnios, intrauterine growth retardation, pulmonary hypoplasia, short umbilical cord and lethality. Autopsy revealed no thoracal or abdominal viscera anomalies and examination of the brain, spinal cord and peripheral nerves did not disclose any pathological changes. Light microscopy, immunohistochemistry and electron microscopy of skeletal muscles demonstrated immature muscles with some fibril disorganisation and abnormal immunoreactivity for actin and desmin. Subsequent molecular genetic analysis revealed a maternal diagnosis of myotonic dystrophy. The retarded growth and maturation of skeletal muscle observed in the presented cases correspond with previous findings in neonatal myotonic dystrophy. A well-defined myopathy can thus result in the fetal akinesia-hypokinesia deformation sequence.