Dr Molly Crenshaw shares a powerful neonatal case of treatable molybdenum cofactor deficiency, where rapid biochemical diagnosis preceded molecular confirmation—but the infant deteriorated before disease-altering therapy could be started. This Shortcast highlights the critical value of urgent biochemical testing, evolving therapies, and the narrowing window for intervention in severe neonatal metabolic disease.Treatable Neonatal Molybdenum Cofactor Deficiency: Rapid Demise Despite Rapid Biochemical DiagnosisMolly M. Crenshaw, et alFirst published: 11 January 2026 https://doi.org/10.1002/jmd2.70061