We report, for the first time, the outcome of three children born to two women with untreated glutaric aciduria type I (GA I). Isolated hypocarnitinemia in neonatal screening in one baby allowed the identification of the disease in his mother, who was undiagnosed so far and had had a previous daughter. The other baby was born to an already diagnosed mother who was not treated; newborn screening in the child reflected the metabolic state of the mother. Biochemical abnormalities returned to normal within one week. At the age of 4 months, neuroimaging showed Sylvian enlargement in both infants and bilateral temporal arachnoid cysts in one. Physical and neurological developments were normal for the three patients at ages 2 and 5 years. We conclude that long-term follow up will determine the true impact of GA I in such children.