Tethered Cord Syndrome and Spinal Epidural Lipomatosis in a Child With RALA -Associated Hiatt-Neu-Cooper Syndrome.

Pathogenic variants in RALA cause Hiatt-Neu-Cooper syndrome, a rare and clinically complex neurodevelopmental condition characterized by developmental delay, hypotonia, and intellectual disability, with distinctive craniofacial features. The disease is also associated with variably occurring seizures, macrocephaly, and autism spectrum disorder. Reported manifestations have primarily involved the central nervous system, and structural spinal abnormalities have not been described to date. Here we report a child with a de novo RALA missense pathogenic variant, c.73G>A (p.Val25Met), who presented with features consistent with RALA-associated neurodevelopmental syndrome and subsequently developed progressive lower extremity weakness. Somatosensory evoked potentials were abnormal, and spinal MRI demonstrated spinal epidural lipomatosis. Surgical exploration confirmed tethered cord syndrome with a fatty filum terminale. The patient underwent surgical detethering, followed by marked postoperative improvement in motor function. This case expands the phenotypic spectrum of RALA-associated disease to include surgically treatable lumbosacral pathology. Consideration of structural spinal abnormalities may be warranted in children with RALA-related neurodevelopmental syndrome who develop new or progressive motor symptoms, as timely intervention may substantially improve functional outcomes.