All of the following can be a cause of anterior crossbite EXCEPT:

Microglossia (a small tongue) is not a recognized contributor to anterior crossbite. Recognized causes include deflected eruption paths from over-retained or ankylosed primary teeth, certain oral habits, trauma, and skeletal Class III growth patterns — if anything, an enlarged tongue (macroglossia) is more often discussed in relation to dental arch/occlusion problems, not a small one.