Spectrum of fetal limb anomalies

Purpose: Antenatal detection of limb anomalies is not uncommon, and pregnancies are usually terminated in view of the expected physical handicap. The aim of this retrospective observational study is to delineate the spectrum of fetal limb anomalies and provide evidence in support of complete postnatal evaluation in establishing recurrence risk.

Methods: We present 54 cases of limb malformations detected antenatally and discuss the spectrum of abnormalities, the utility of fetal autopsy, and genetic testing to establish recurrence risk in subsequent pregnancies.

Results: 16/54 cases were isolated radial ray anomalies. There were five cases of amniotic band syndrome, five limb body wall complex cases, three VACTERL (vertebral defects, anal atresia, cardiac defects, tracheo-esophageal fistula, renal anomalies, and limb abnormalities) associations, one case of sirenomelia, two cases of limb pelvis hypoplasia, and one case of OEIS (Omphalocele Exstrophy Imperforate anus and spinal defects). Four fetuses with non-isolated radial ray anomaly had trisomy 18. One case with bilateral radial ray defect had a mutation in the FANC-E gene confirming fanconi anemia. Twelve cases were unclassified.

Conclusion: Autopsy is the most important investigation in fetuses with limb anomalies. We suggest chromosomal microarray (CMA) as a first-tier test after autopsy. However, in cases of bilaterally symmetrical limb anomalies, in case of previous similarly affected child, or history of consanguinity, whole exome sequencing (WES) can be offered as the primary investigation, followed by CMA if WES is normal.