First case report of effective and safe application of cannabidiol to treat concurrent ALG3-CDG and Lennox-Gastaut Syndrome.

This study presents the first reported case of a Korean patient with Alpha-1,3-Mannosyltransferase-Congenital Disorder of Glycosylation (ALG3-CDG), characterized by a novel maternally inherited missense mutation and a previously reported paternally inherited nonsense mutation. The patient exhibited typical ALG3-CDG manifestations, including developmental delays, epilepsy, and multisystem involvement, alongside a diagnosis of Lennox-Gastaut Syndrome (LGS). Cannabidiol therapy, combined with dietary management, led to seizure freedom for over 13 months, significant EEG improvement, and enhanced developmental outcomes. This case underscores the potential of cannabidiol as a promising treatment strategy for patients with ALG3-CDG and refractory epilepsy, broadening therapeutic perspectives for this rare disorder.