Overview

Macroglossia occurs commonly in people with Down syndrome (DS). The term describes the enlargement of the tongue, which often causes its protrusion beyond the dental arch. This anatomical abnormality can affect important functions of the human body, such as feeding, talking and even breathing. 

Down’s syndrome (DS) is a genetic condition diagnosed in newborns, affecting about one in 700 live births. Also known as Trisomy 21, this disorder is caused by the presence of an extra chromosome 21 in each cell of the body. A person with DS can have variable intellectual disability, growth deficiency, characteristic facial features (including macroglossia), hypotonia (low muscle tone) and increased joint laxity. Malformations can also be present, including congenital heart defects and digestive, neurological, haematological and endocrinological problems.^1,2

This article aims to provide information about macroglossia in people with Down’s syndrome. It covers general aspects of both conditions, characteristics of DS, the frequency of occurrence of macroglossia in DS, symptoms, diagnosis, and management, highlighting the importance of early intervention in improving the outcome and overall quality of life for people with DS. 

What is macroglossia?

Macroglossia is a term used to describe the painless enlargement of the tongue. Also known as “giant tongue”, macroglossia is more frequently seen in children rather than adults. Usually, it is a symptom of congenital genetic conditions, such as DS, Beckwith-Wiedeman syndrome, or muchopolysacharisodis (Hurler or Hunter syndrome). It can also be a symptom in some acquired conditions (develop after birth), such as cancer, amyloidosis, hypothyroidism, acromegaly, or infections, such as diphtheria. Occasionally, isolated congenital macroglossia can be a condition ‘on its own’, and is genetically inherited in an autosomal dominant manner.^3,4

Besides a classification of ‘congenital’ or ‘acquired’, macroglossia can also be categorised as ‘true’ or ‘relative’ (false, or pseudomacroglossia). 

True macroglossia is characterised by the painless enlargement of the tongue, causing its protrusion outside of the mouth. The cause of true macroglossia is usually an underlying condition, such as infection, disease, or cancer. 

Relative macroglossia happens when the tongue appears enlarged, compared to the adjacent oral structures which are disproportionately small. Frequently, in DS, the muscle hypotonia (floppiness) of the tongue, combined with other anatomical oral and facial traits, results in false macroglossia (pseudomacroglossia).^3,4

The diagnosis is based on the clinical assessment of the tongue and resulting symptoms, such as excessive drooling (sialorrhea), eating and swallowing difficulties, varying degrees of airway obstruction, teeth and mandibular deformities, and other complications. 

Diagnosing macroglossia usually involves a team of healthcare specialists, including a medical geneticist, dentist, orthodontist, maxillofacial surgeon, radiotherapist, speech therapist, and even psychiatrist (if the individual’s macroglossia also deeply impacts the social and emotional state of the person).³

Further information on macroglossia can be found at, ‘What is macroglossia?’ 

What is Down’s syndrome? 

Down’s syndrome (DS) is the most commonly known genetic disorder in humans. It is a consequence of the presence of an extra chromosome 21, that causes the characteristic physical features and developmental problems in affected people.

The syndrome’s severity is variable, and the symptoms are different between affected individuals. The clinical description includes a distinctive face, hypotonia (low muscle tone), a single palmar crease, congenital heart disease, obstructive sleep apnoea (OSA), and immune, digestive, endocrinological, eye, ear, and dental problems. People with it also experience delays in reaching the developmental milestones regarding walking, speaking, learning (with mild to moderate learning difficulties), and social and emotional skills.²

The chance of having a baby with DS increases with maternal age. High-risk signs, such as increased nuchal translucency in the foetus, can be identified even in the first trimester during an ultrasound examination. Cardiac and digestive malformations can be identified in the second-trimester ultrasound examination.

A prenatal (before birth) diagnosis of DC via karyotype analysis (assessment of the whole set of chromosomes) following amniocentesis or chorionic villus sampling can help families early in the pregnancy by bringing clarity about their child’s condition, and give further help by allowing them to properly prepare and deal with the possible complications of the disease, while improving the overall outcome of the patient.² 

Further information about Down’s syndrome can be found at, ‘What is Down’s syndrome?’

Macroglossia and Down’s syndrome

How common is macroglossia in DS patients?

Macroglossia is one of the most well-known clinical features in people with DS. Macroglossia can also be difficult to diagnose in DS because it is a relative type of macroglossia, and so it also involves other factors, such as the mouth, lips, teeth, and the bones of the face.³

What causes macroglossia in DS patients? 

The tongue is part of the stomatognathic system (mouth, teeth, tongue, lips, and associated oral structures in terms of their relationship with chewing, swallowing and speech). Its functioning is altered in people affected by DS. About 69% of people with DS have problems concerning the face and the jaw. They have a small mouth, a gothic palate (narrow roof of the mouth), a prognathic (protruding) jaw, maxillary hypoplasia and an anterior open bite (malocclusion), and lip incompetence (incomplete closure of the lips) – factors favouring macroglossia.¹

Two well-known traits of DS, Hypotonia and psychomotor developmental delays, contribute to the dysfunction of the stomatognathic system. The hypotonia affects the masseter muscle and the tongue and the lips, causing the tongue’s protrusion in resting position beyond the dental arches, and the incomplete closure of the lips.¹

People with DS also experience irregularities of the facial bones, including the palate, which are reduced in dimensions (maxillary hypoplasia). The structure of the palate is referred to as ‘high arched’, ‘gothic’, or ‘narrow’ – and the midface of the patient appears underdeveloped. Therefore, relative to the other structures of the stomatognathic system, the hypotonic tongue appears bigger, explaining the “false macroglossia”, observed in these individuals.^1,5

What are the symptoms of macroglossia in people with DS? 

Eating and speaking difficulties

The false macroglossia causes the affected child to adopt a resting facial position with an open mouth and a protruding tongue. The dysfunctional stomatognathic system causes eating and speaking difficulties. 

The tongue is too large, too long, hypotonic, and has low motility. The underdevelopment of the midface, the hypotonia and low motility of the muscles of the lips, palate, and of the muscles involved in chewing and facial expression, also contribute to the eating and speaking difficulties.

Newborns experience feeding problems due to sucking and swallowing problems, and later on, children and adults experience speaking and language difficulties.⁶ 

Oral and dental problems

Due to the higher frequency and severity of periodontal disease, the oral health status of people with DS requires greater dental health attention and more thorough oral hygiene practices compared to the general population. 

People affected by Down’s syndrome also have increased tonsillar volume, which combined with the maxillary hypoplasia, can cause airway obstruction and produce open-mouthed breathing. This causes sialorrhea (excessive drooling), resulting in dryness of the tongue or oral tissues. This leads to a fissured tongue, lip lesions, and angular cheilitis (cracked sores in the mouth corners).^7,8,9

The permanent moisture at the corners of the mouth favours the development of oral thrush – a fungal infection with Candida albicans.⁹

People with DS, macroglossia and stomatognathic dysfunction also experience dental problems. The anterior, prognathic, abnormal position of the jaw, is a causative factor of malocclusion with an anterior open bite. 

Further dental problems can include delayed tooth eruption, enamel hypoplasia or hypocalcification, disproportionately small tooth size (microdontia), hypodontia (missing teeth), diastema (gaps between the teeth), and impacted, or displaced teeth.^1,7,9,10

Obstructive sleep apnoea

Obstructive sleep apnoea (OSA) affects up to 79% of children with DS, and almost half of the instances are moderate-to-severe. 

Usually, children with adenotonsillar hypertrophy (enlarged tonsils and adenoids) are at risk of developing OSA, but children with DS have additional risk factors, such as generalised hypotonia, relative macroglossia, maxillary hypoplasia, narrow palate, narrow nasopharynx, laryngotracheal anomalies, and an apparent increased upper airway collapsibility. Furthermore, they are predisposed to obesity and hypothyroidism, and their immune system deficiencies lead to more frequent respiratory infections. 

All these factors create the necessary conditions for developing obstructive sleep apnoea. The management and treatment of OSA in people with DS might be challenging, due to the ineffectiveness of standard medication therapies for mild OSA.^11,12 

How is macroglossia diagnosed in DS patients? 

Clinical examination

Macroglossia can be diagnosed in a person with DS clinically, by considering the appearance of the tongue, whether it protrudes beyond the dental arch, the presence of sialorrhea, and the evaluation of the stomatognathic system. A multidisciplinary team of healthcare specialists is needed to properly diagnose, treat and manage people with DS and macroglossia.^3,9,13

Differential diagnosis

Although macroglossia is a common feature of DS, there are numerous other causes of macroglossia in the general population and an overlap with DS, or multifactorial causation (hypothyroidism, acromegaly, diabetes lymphangioma) might be possible, so careful clinical assessment is necessary.⁴

Investigations

Macroglossia can be detected even prenatally, during the ultrasound examination. Maxillary hypoplasia can also have screening value, indicating a high risk for anomalies in the same way that the increased nuchal translucency does. The evaluation of the maxillary hypoplasia by imaging can also predict the possibility of developing malocclusion or OSA when assessed and monitored in different stages of the growth process.⁵

Other imaging studies, such as an MRI scan, can also be used in the evaluation of macroglossia in someone with DS, especially if the person also presents with airway obstruction, or OSA.¹¹

What is the treatment?

Macroglossia requires treatment as early as possible in DS patients – even as early as in the first few months of life. 

Macroglossia and the underdevelopment and dysfunction of the stomatognathic system can be indications for a complex interdisciplinary, rehabilitative treatment, that involves the use of a stimulating palatal plate (an appliance worn in the mouth which aims to improve the posture of the tongue and lips), complemented by a specific type of physiotherapy called orofacial regulation therapy (ORT) or oral muscular stimulation therapy, speech-language-hearing therapy and adequate support for family long-term involvement. 

It may also involve the otolaryngologist, maxillofacial surgeon, orthodontist, psychologist, and dental hygienist. This complex process aims to improve the motility and the muscular tone of the tongue and lips, the expansion of the oral cavity – allowing the tongue to rest inside the mouth behind the dental arches, obtaining the closure of the mouth and sialorrhea (drooling) reduction. It also has a preventive role, avoiding potential complications such as speech impairment, teeth and jaw abnormalities, malocclusion, and airway obstruction.^1,6,13

Oral muscular stimulation therapy has proved to be beneficial to maxillary development, prevent the narrowing of the palate, and improve oral function when started as soon as 6 to 9 months of life.^5,9 

The majority of instances of macroglossia in people with DS need orthodontic treatment because about 83% of DS patients present with severe malocclusions. They are also known to have a poorer “oral health status”, so an oral hygienist’s care is needed.⁹

In general, conservative case management and treatment are preferred for macroglossia, but in rare and severe cases (10%) where the individual has significant speech and feeding difficulties, or airway obstruction, surgery is considered.³ 

Surgery for macroglossia in Down’s syndrome is very rarely indicated – usually only when it interferes with the breathing process. It is called tongue reduction surgery. Another type of surgery is orthognathic surgery but is also rarely indicated, and orthodontic treatment is needed before, during, and following the surgery. 

Summary 

Macroglossia is a common trait in people with Down’s syndrome. Early detection and effective management and treatment are fundamental for obtaining an overall improved health status and quality of life. 

The approach used in dealing with macroglossia in people with Down’s syndrome can also have a preventive role, avoiding the possible complications – impaired speech, feeding difficulties, OSA, even breathing problems due to upper airway obstruction – caused by an advanced dysfunction of the stomatognathic system, and a protruding, hypotonic tongue. 

A multidisciplinary team of healthcare specialists and the long-term support and dedication of the family or caregivers are essential to meet the unique set of needs presented by each person with DS and macroglossia.