The incidence increases with maternal age. The syndrome results from nondisjunction and the affected individual has an extra chromosome 21. These patients have numerous characteristic physical findings and mental deficiency. The macroglossia is accentuated by their general hypotonia, causing some authors to refer to this as a relative or pseudomacroglossia. The histology shows hyperplasia and hypertrophy similar to Beckwith-Wiedmann Syndrome.
Macroglossia causes a variety of signs and symptoms.
These include tongue protrusion, which exposes the tongue to trauma. This exposure also leads to mucosal drying and recurrent upper respiratory tract infections. Other symptoms include speech impediment, swallowing difficulties, airway obstruction, drooling, and failure to thrive. Evaluation of macroglossia begins with a careful history and physical exam to identify any undiagnosed syndrome. Laboratory tests are guided by clinical suspicions.