Résumé
The expansion of newborn screening in France (2023–2025) to include carnitine metabolism disorders has increased false positives, often due to unsuspected maternal metabolic conditions. We report the first french incidental diagnosis of a glutaric acidemia type I in a mother following a low C0 carnitine level detected on her newborn's screening. Genetic analysis revealed a previously undescribed mutation in the GCDH gene at a homozygote state consistent with an asymptomatic but high-excretor biochemical profile.