Bilateral choanal atresia in premature monozygotic twins.

Bilateral congenital choanal atresia is a relatively rare anomaly of the upper airway, which may cause life-threatening respiratory emergency and require rapid diagnosis and treatment. This condition usually occurs sporadically, but has also been rarely described in siblings. We present monozygotic premature twin infants with identical findings of bilateral choanal atresia and no other associated anomalies. To our knowledge, this is the first report of such an occurrence.