Macroglossia is the abnormal enlargement of the tongue. In rare cases, macroglossia occurs as an isolated finding that is present at birth (congenital). In many cases, macroglossia may occur secondary to a primary disorder that may be either congenital (e.g., Down syndrome or Beckwith-Wiedemann syndrome) or acquired (e.g., as a result of trauma or malignancy). Symptoms and physical findings associated with macroglossia may include noisy, high-pitched breathing (stridor), snoring, and/or feeding difficulties. In some cases, the tongue may protrude from the mouth. When inherited, macroglossia is transmitted as an autosomal dominant genetic trait.
Macroglossia is a disorder characterized by a tongue that is large in proportion to other structures in the mouth. In the congenital type of the disorder, protrusion of the tongue from the mouth may interfere with feeding of the infant. Later, talking may be affected. The large size of the tongue may also cause abnormal development of the jaw and teeth, resulting in misaligned or protruding teeth. Ulceration and dying tissue on the tip of the tongue may be other symptoms of the disorder.
Macroglossia may be found in individuals affected by certain inherited or congenital disorders including Beckwith-Wiedemann syndrome, acromegaly, primary amyloidosis, congenital hypothyroidism, Down syndrome, Apert syndrome, and many others.
Macroglossia may also be a sign of certain acquired disorders, including malignancies, metabolic/endocrine disorders, and inflammatory or infectious diseases.
In rare cases, macroglossia is an inherited disorder not associated with any other cause, either congenital or acquired. In such instances, the disorder is genetically transmitted as an autosomal dominant trait.
Dominant genetic disorders occur when only a single copy of an abnormal gene is necessary for the appearance of the disease. The abnormal gene can be inherited from either parent, or can be the result of a new mutation (gene change) in the affected individual. The risk of passing the abnormal gene from affected parent to offspring is 50% for each pregnancy regardless of the sex of the resulting child.
Isolated autosomal dominant macroglossia is very rare, with about 50 cases reported in the medical literature. The prevalence in other instances depends on the underlying disorder for which the macroglossia is secondary. For example, macroglossia occurs in most cases of Beckwith-Wiedemann syndrome, and the prevalence of that syndrome is estimated at 1 in 17,000 births.
Infants born with isolated autosomal dominant macroglossia present with the obvious sign at birth. A family history and physical exam can confirm the diagnosis.
The tongue may be reduced in size by surgery with remodeling of the mouth and orthodontic procedures.
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