Definition: Prolonged decrease or absence of fetal motion results in a group of anomalies, characterized in their full blown appearance by abnormal limb positions, craniofacial deformations, growth restriction, polyhydramnios, lung hypoplasia and short umbilical cord. The deformities are usually symmetric and the severity of the deformities often increases distally along the involved limb. FADS is usually generalized but focal anomalies exist. Bimelic akinesia affects more often the lower limbs.

Inheritance

 autosomal recessive transmission (50%)

• occurence in monozygotic twins (#11204282#)

 autosomal dominant transmission (#2070954#)

Synopsis

 systemic anomalies

• small for gestational age
• intrauterine growth retardation
• premature birth
• stillborn (30%)

 craniofacial anomalies

• rigid face (expressionless face)
• long philtrum
• micrognathia
• small, posteriorly rotated ears
• poorly folded ears
• prominent eyes
• hypertelorism
• telecanthus
• short palpebral fissures
• ptosis
• depressed nasal tip
• small mouth
• high arched palate
• cleft palate
• short neck

 thoracic anomalies

• pulmonary hypoplasia
• small thorax
• thin ribs

 digestive anomalies

• short-gut syndrome

 cryptorchidism

 limb anomalies

• hip ankylosis
• elbow ankylosis
• knee ankylosis
• thin, gracile long bones
• ulnar deviation of hands
• camptodactyly
• absent dermal ridges or sparse dermal ridges
• ankle ankylosis
• rocker-bottom feet
• talipes equinovarus

 neurological anomalies

• neurogenic muscle atrophy
• hydrocephalus
• microgyria
• cerebellar hypoplasia
• absent septum pellucidum
• cavum septum pellucidum

 placental et annexial anomalies

• polyhydramnios
• small or abnormal placenta
• short umbilical cord

Etiology

FADS can be secondary to neurogenic diseases, myogenic anomalies, and restrictive dermopathies. The most common pattern of transmission is autosomal recessive. Due to the various possible etiologies, the prediction of recurrence is difficult, varying from 0-15% (when associated with primary brain malformation) to 25% (myogenic etiology).

 fetal neuronopathy

• anterior horn cell loss and lateral corticospinal tract degeneration in spinal cord, with marked muscular atrophy (#11810649#)

 fetal myopathy (#11555456#, #2262870#)

• congenital myotonic dystrophy (#7606895#)

 maternal myasthenia gravis (#10797415#)

 fetal cerebral anomalies

• lissencephaly type 3 (MIM.601160)
• severe cerebrospinal malformations
• Dandy-Walker malformation (#11810649#)
• acquired intrauterine brain damage (#1891100#)
• bilateral opercular polymicrogyria (#8972538#)

Associations

 cystic hygroma (#11332983#)
 thymic and systemic T-cell lymphoid hyperplasia (#11070126#)

Differential diagnosis

 trisomy 18

• craniofacial, limb, and thoracic anomalies

 uterine malformation

References

 Yfantis H, Nonaka D, Castellani R, Harman C, Sun CC. Heterogeneity in fetal akinesia deformation sequence (FADS): autopsy confirmation in three 20-21-week fetuses. Prenat Diagn. 2002 Jan;22(1):42-7. PMID: #11810649#