A rare cause of cyanosis: Congenital methemoglobinemia

A 13-month-old infant, born from a consanguineous marriage. She presented isolated cyanosis. Physical examination was normal. Pulsed oxygen saturation was 94% in room air. Methemoglobin level was 39.4%. The diagnosis of congenital methemoglobinemia type I was retained. She was successfully treated with methylene blue infusions and ascobic acid.