A case of a 2-month-old Down syndrome infant without structural cardiac anomaly is reported in whom management of gastroesophageal reflux (GER) using duodenal-tube feeding successfully treated pulmonary arterial hypertension (PAH). Based on this case, examination for GER is recommended for infants who present with PAH, especially those with Down syndrome who have no cardiac anomalies. (Circ J 2009; 73: 2352-2354)
