Rethinking Delivery Timing in Prenatally Diagnosed Spinal Muscular Atrophy: A Case Report With 2‐Year Follow‐Up

ABSTRACT Objective We describe the clinical course and outcome of a prenatally diagnosed infant with spinal muscular atrophy (SMA) treated immediately after early‐term birth and highlight considerations regarding delivery timing and neonatal management. Methods This male infant had a family history of SMA type 1A. Chorionic villus sampling confirmed homozygous SMN1 deletion with two SMN2 copies. Serial ultrasounds were reassuring, and delivery was induced at 37 + 0 weeks. Nusinersen was initiated at 24 h, followed by onasemnogene abeparvovec‐xioi at 9 days. Results At birth, he exhibited respiratory distress, hypotonia, and reduced spontaneous movements. Cerebrospinal fluid neurofilament light chain on day 1 was markedly elevated (12 273 pg/ml), indicating substantial prenatal neuronal injury. Motor function improved: CHOP‐INTEND scores increased from 26/64 (day 8) to 64/64 (16 months). Independent ambulation was achieved at 18 months. However, standardized developmental testing at 25 months demonstrated persistent gross motor and expressive language delay. Interpretation This patient illustrates that clinically significant motor neuron injury may occur in utero despite reassuring fetal surveillance. It suggests that the optimal treatment window may already be closing by term and supports consideration of elective late‐preterm delivery and standardized institutional protocols for the early neonatal management of prenatally diagnosed SMA.