Endothelial nitric oxide synthase polymorphisms associated with abnormal nitric oxide production are not over-represented in children with Down syndrome.

Objective: Down syndrome patients are at increased risk for developing pulmonary hypertension (PHTN). Nitric oxide (NO) is an important factor for pulmonary vasoreactivity. Various endothelial nitric oxide synthase (eNOS) polymorphisms have been shown to affect NO.