Amniotic Band Syndrome (ABS) is a rare congenital disorder caused by fibrous amniotic strands that can entangle fetal structures, producing defects ranging from constriction rings to severe limb malformations. Prenatal detection remains challenging because diagnosis often relies on indirect imaging findings rather than direct visualization of amniotic bands. We report a severe four-limb ABS case with postnatal diagnosis, genetic evaluation, and multidisciplinary management. A male neonate was delivered at 31 + 6 weeks after an uncomplicated pregnancy with normal prenatal ultrasounds. Postnatally, malformations involved all four limbs: severe right‑hand acrosyndactyly with thumb hypoplasia; left hand distal phalanx aplasia of the third digit with a circumferential constriction band and a rudimentary distal phalanx of the fourth digit; and lower‑limb syndactyly/hypoplasia with amniotic rings. Color Doppler ultrasound confirmed distal perfusion. No visceral or craniofacial anomalies were detected. Genetic testing identified a heterozygous FAM20C variant of uncertain significance. Orthopaedic and plastic surgery assessments recommended staged reconstructive procedures to optimize function. Severe ABS may present unexpectedly despite normal prenatal imaging. The clinical relevance of this case lies in the extent of four-limb involvement, the postnatal phenotypic classification, and the need for early multidisciplinary planning. Early postnatal assessment and coordinated multidisciplinary care are essential for surgical planning, follow‑up, and optimization of limb function.
Colombo et al. (Wed,) studied this question.