Preemptive immunotherapy for fetal acetylcholine receptor antibody disorder (FARAD): from recurrent pregnancy losses to a healthy infant - a case report

Maternal antibodies against the fetal acetylcholine receptor (fAChR) can cause fetal acetylcholine receptor antibody-related disorders (FARAD), a rare but important cause of arthrogryposis multiplex congenita (AMC) and Fetal Akinesia Deformation Sequence (FADS), with recurrence rates up to 100%. Unlike genetic causes, FARAD may respond to maternal immunotherapy, yet standardized treatment protocols are lacking. We report four pregnancies in an asymptomatic mother with confirmed fAChR antibodies. After three fetal losses due to FARAD and two unsuccessful treatment attempts initiated only after sonographic abnormalities, a healthy infant was delivered in the fourth pregnancy following a pre-planned preemptive approach. Treatment, initiated at week 10 of gestation, consisted of plasmapheresis (PLEX) and subsequent weekly high-dose intravenous immunoglobulin (IVIg). Fetal serum after birth confirmed fAChR antibodies on cell-based assays (live and fixed). This case series underscores the importance of recognizing fAChR antibodies as differential diagnosis of AMC in asymptomatic mothers and of early, consistent antibody-reducing therapy to prevent FARAD-related pregnancy losses.