Hemoglobin I-Toulouse: A rare hemoglobinopathy presenting with low oxygen saturations.

We report a child with persistently low oxygen saturations (SpO2 90%-92%) [normal SpO2 > 98%], with delayed diagnosis due to the co-existing congenital pulmonary airway malformation with possible arterio-venous malformation. The diagnosis was only achieved after low oxygen saturations incidentally discovered from the child's father. The eventual cause was Hemoglobin I-Toulouse, making both patients the first reported cases with low oxygen saturations.