First-trimester Detection of Isolated Unilateral Complete Radial Aplasia during Nuchal Translucency Screening: A Case Report

Abstract

Radial ray defects are congenital upper-limb anomalies involving the radius, radial carpal structures and thumb. We report a 24-year-old primigravida in whom left-sided complete radial aplasia with radial club hand and absent thumb (Bayne-Klug Type IV) was identified at a routine first-trimester nuchal translucency scan at 13 weeks six days of gestation. Detailed sonographic examination showed no other structural anomaly or soft marker. Chorionic Villus Sampling (CVS) was performed at 14 weeks one day for conventional karyotyping, with foetal DNA stored for possible future testing. The couple elected medical termination without awaiting the result. Expulsion followed mifepristone and misoprostol and was complicated by retained placenta requiring emergency suction evacuation and transfusion of one unit of packed red cells. Karyotyping was subsequently reported as normal. Postexpulsion radiography confirmed complete absence of the left radius with a bowed ulna and absent thumb. Chromosomal microarray and exome sequencing were not performed and no autopsy was undertaken; the defect was therefore described as apparently, rather than truly, isolated.