Airway obstruction due to a rudimentary premaxilla in holoprosencephaly.

We present two infants with holoprosencephaly and clefts of the primary palate, who developed nasal airway obstruction due to a previously undocumented cause: a ball-valve-like action of a rudimentary premaxilla, which was extremely mobile on a soft tissue stalk. In such patients, the importance of intranasal examination to identify a rudimentary premaxilla, in order to preserve it, and if necessary, surgically stabilize it, is illustrated.