Which systemic condition can cause macroglossia (enlarged tongue)?

Macroglossia (pathologically enlarged tongue) is a hallmark finding of systemic amyloidosis, caused by the deposition of amyloid protein in the tongue tissue. The tongue appears diffusely enlarged, firm, and may show scalloping from tooth impressions. Other causes of macroglossia include: hypothyroidism (not hyperthyroidism), acromegaly, Down syndrome, Beckwith-Wiedemann syndrome, and hemangioma/lymphangioma. In amyloidosis, other oral findings include petechiae, purpura, and submandibular gland enlargement. Macroglossia can cause speech difficulties, dysphagia, and sleep apnea.