Monozygotic twins with fetal akinesia: the importance of clinicopathological work-up in predicting risks of recurrence.

Fetal Akinesia Deformation Sequence (FADS) or Pena-Shokeir Sequence is a heterogeneous group of disorders in which prolonged decrease or absence of fetal movements results in a series of deformational anomalies: multiple contractures, pulmonary hypoplasia, craniofacial anomalies, polyhydramnios, intrauterine growth retardation, and short umbilical cord. Three sets of monozygotic twins, and their affected sibs, are presented. Detailed pathological work-up established that the two pairs of twins concordant for FADS were of myogenic etiology while the set discordant was due to anoxic-ischemic damage. In the myogenic cases, the rate of recurrence was high, in agreement with the findings from the study on arthrogryposis multiplex congenita of myogenic origin. In light of these findings, in sporadic cases of myogenic FADS, counselling, a recurrence risk of 25% seems prudent. In neurogenic cases associated with primary cerebral malformations, there are cases cited in the literature that are clearly recessive as indicated by affected sibs, but many reported are isolated occurrences. Therefore, in this scenario, giving a recurrent risk of 10-15% appears appropriate. In light of autosomal recessive spinal muscular atrophy and reports of familial FADS due to primary anterior horn cell loss, counselling a 25% risk seems prudent. In cases due to anoxic-ischemic damage, offering a low recurrent risk of 1% appears justified.