Triangular-shaped open mouth

What it means

A facial appearance characterized by a permanently or nearly permanently opened mouth, in which the upper lip is tented in a way that the opened mouth has the appearance of a triangle.

Rare diseases that can present with this1

The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.

Part of the broader category