A tongue that rests between the lips is one of the most recognizable features of Down syndrome, and most people assume the tongue is simply oversized. The usual cause is less about the tongue and more about the space and muscles around it.1PubMed. Relative rather than absolute macroglossia in patients with Down syndrome: implications for treatment of obstructive sleep apnea In most people with Down syndrome the tongue is a normal size. It sticks out because the mouth and upper jaw are smaller than usual and because the muscles of the tongue, lips, and jaw are low in tone, so the tongue rests forward and the mouth falls open. That distinction matters to families, because it shapes which treatments actually help.
A Normal Tongue in a Smaller Mouth
Scans of children with Down syndrome show their tongues are not truly oversized, only large compared with the bony space of the mouth.2PubMed. Relative rather than absolute macroglossia in patients with Down syndrome: implications for treatment of obstructive sleep apnea Your child’s doctor or therapist may call this relative macroglossia, meaning a normal tongue in a small mouth.3Global Down Syndrome Foundation. Resource Guide to Oral Motor Skill Difficulties in Children with Down Syndrome Some older studies counted “large tongue” in anywhere from about a third to over 9 in 10 people with Down syndrome, largely because a crowded tongue looks big.4PubMed Central. Oral soft tissue conditions in Down syndrome patients
The reason is the shape of the face. The middle part of the face develops smaller in Down syndrome.5CMDSS. Oral Development – CMDSS The upper jaw is small, and the roof of the mouth is narrow and often high-arched.6CMDSS. Oral Development – CMDSS7Global Down Syndrome Foundation. Resource Guide to Oral Motor Skill Difficulties in Children with Down Syndrome There is less room for teeth and for the tongue, which spills forward between the lips.8CMDSS. Oral Development – CMDSS An average tongue in a small upper and lower jaw also can’t move freely.9Global Down Syndrome Foundation. Resource Guide to Oral Motor Skill Difficulties in Children with Down Syndrome
The tongue may simply rest on the lower lip or teeth rather than being pushed out on purpose. A narrow, high palate leaves no groove for the tongue to tuck up into, so it can’t spread out flat against the roof of the mouth the way it normally does at rest. With the space above it taken up by the palate’s shape, the easiest place for it to settle is forward and low. Babies with this mouth shape may show the forward tongue from the first weeks, which is one reason it is noticed so early.
The protrusion is not a bad habit, and it is not a sign of lower intelligence. It is a physical fit problem present from birth. It can change as the face and jaw grow, though the mouth stays relatively small.
Low Muscle Tone Lets the Tongue Rest Forward
Low muscle tone is one of the main features of Down syndrome and can affect any muscle.10PubMed Central. Evaluation of the masticatory muscle function, physiological sleep variables, and salivary parameters after electromechanical therapeutic approaches in adult patients with Down syndrome: a randomized controlled clinical trial It is especially marked in the chewing muscles and the muscles of the mouth and throat.11PubMed Central. Evaluation of the masticatory muscle function, physiological sleep variables, and salivary parameters after electromechanical therapeutic approaches in adult patients with Down syndrome: a randomized controlled clinical trial The tongue and jaw tend to sag, so the mouth hangs open and the tongue slides forward.12Global Down Syndrome Foundation. Resource Guide to Oral Motor Skill Difficulties in Children with Down Syndrome
Day to day, this can look like lips that stay parted even during quiet play or TV. Tiredness, illness, or deep concentration can make the tongue come out more, and many families notice it most at the end of the day. Colds and allergies that block the nose push a child to breathe through the mouth, which lets the jaw drop and the tongue move forward.
Low tone is different from weakness. The muscles are slower to switch on and hold a position, but they can still work, and they respond to practice. Activities that ask the lips and tongue to work, such as drinking through a straw, can build control over time. A tongue that rests out is a starting point for therapy rather than a fixed trait.
Early feeding habits may shape the bite further. In children and teens with Down syndrome, about 1 in 5 has an open bite where front teeth don’t meet and about 1 in 3 has a crossbite.13Angle Orthodontist. Feeding and nonnutritive sucking habits and prevalence of open bite and crossbite in children/adolescents with Down syndrome Using a bottle beyond age 2 was linked to both open bite and crossbite.14Angle Orthodontist. Feeding and nonnutritive sucking habits and prevalence of open bite and crossbite in children/adolescents with Down syndrome Pacifier or finger sucking past age 2 was linked to crossbite.15Angle Orthodontist. Feeding and nonnutritive sucking habits and prevalence of open bite and crossbite in children/adolescents with Down syndrome Easing off bottles and pacifiers around age 2 may help the bite, and with it the room for the tongue.
A tongue resting between the teeth can keep the front teeth apart, and an open bite in turn leaves a gap the tongue fills. A pediatric dentist can track this from the first teeth onward.
How It Affects Eating, Drinking, and Speech
Low tone in the mouth and throat muscles can make speech, swallowing, and chewing harder.16PubMed Central. Evaluation of the masticatory muscle function, physiological sleep variables, and salivary parameters after electromechanical therapeutic approaches in adult patients with Down syndrome: a randomized controlled clinical trial Children with Down syndrome had more feeding and swallowing trouble than children with other developmental delays, with liquids, purées, and solid food alike.17International Journal of Developmental Disabilities. Feeding and swallowing difficulties: comparing children with Global Developmental Delay, Down syndrome, and typical development Closing the jaw, moving the tongue, and shaping food into a swallowable lump were all harder.18International Journal of Developmental Disabilities. Feeding and swallowing difficulties: comparing children with Global Developmental Delay, Down syndrome, and typical development Mealtime behaviors such as spitting food or leaving the table were also more common.19International Journal of Developmental Disabilities. Feeding and swallowing difficulties: comparing children with Global Developmental Delay, Down syndrome, and typical development
At the table, liquid may leak from the lips when a child drinks from a cup, because the lips don’t seal well around the rim. A child may push food forward with the tongue so it comes back out, rather than moving it back to swallow. Meals may run long, or the child may tire and lose interest partway through because chewing takes extra effort. Coughing or a wet-sounding voice during meals is worth mentioning to a doctor, since it can signal swallowing trouble.
A feeding therapist or speech-language pathologist can watch a child eat and drink and suggest changes in textures, cup types, and positioning. Help can start in infancy, and families do not need to wait until problems are obvious.
A mouth that stays open leads to drooling and breathing through the mouth.20PubMed Central. Lip and oral lesions in children with Down syndrome. A controlled study A tongue that can’t move freely also makes clear sounds harder to form. Sounds like t, d, s, and l need the tongue tip to lift and stay behind the teeth. Family members often understand the child better than strangers do. Speech therapy is widely offered and works on both muscle tone and tongue placement.
The Link to Snoring and Sleep Apnea
Obstructive sleep apnea, where the airway repeatedly closes during sleep, is more common and more severe in Down syndrome.21Chest. Sleep-disordered breathing in Down syndrome Low tone in the throat and tongue-base muscles lets the airway partly or fully collapse, causing snoring and pauses in breathing.22PubMed Central. Evaluation of the masticatory muscle function, physiological sleep variables, and salivary parameters after electromechanical therapeutic approaches in adult patients with Down syndrome: a randomized controlled clinical trial The muscle that pulls the tongue forward is also less active, and combined with the small airway this is likely the main cause of blockages.23PubMed Central. Evaluation of the masticatory muscle function, physiological sleep variables, and salivary parameters after electromechanical therapeutic approaches in adult patients with Down syndrome: a randomized controlled clinical trial On scans, a relatively large tongue falling backward in sleep, along with regrown tonsils and adenoids, was the most common reason blockage persisted after surgery.24National Down Syndrome Society. Sleep & Down Syndrome Weight gain, an underactive thyroid, and acid reflux add to the risk.25Chest. Sleep-disordered breathing in Down syndrome
The same tongue behaves differently by day and by night. Awake and upright, a tongue with low tone drifts forward and out of the mouth. Lying down and relaxed in sleep, it falls backward toward the throat and narrows the airway.
Taking out tonsils and adenoids helps many children because it clears space in the throat. It does not change the tongue or the muscle tone around it, so some children still have blockage afterward. That is why doctors often recheck sleep after surgery rather than assuming the problem is fixed.
Loud snoring, gasping, restless sleep, or daytime tiredness are reasons to ask about a sleep study. This is usually an overnight stay with sensors on the skin, and in most cases no needles. It measures breathing pauses and oxygen levels, and the results guide whether treatment such as a breathing machine or surgery is needed.
Therapy and Dental Devices That Help
Myofunctional therapy is exercise and training for the tongue, lips, and face muscles, often given by speech therapists.26European Journal of Paediatric Dentistry. A specific protocol of myo-functional therapy in children with Down syndrome: A pilot study In one small program, 4 of 10 children learned to keep their tongue up against the palate at rest.27European Journal of Paediatric Dentistry. A specific protocol of myo-functional therapy in children with Down syndrome: A pilot study Most could not, because holding the tongue up needs a palate wide enough to fit it.28European Journal of Paediatric Dentistry. A specific protocol of myo-functional therapy in children with Down syndrome: A pilot study Mouth-muscle therapy therefore works best alongside treatment that adds room.
A palatal plate is a small device fitted to the roof of a baby’s mouth that prompts the tongue and lips into better positions.29Boletim de Conjuntura (BOCA). PALATAL MEMORY PLATE IN TRISSOMY 21: BENEFITS OF EARLY INTERVENTION IN OROFACIAL DEVELOPMENT In a small group of infants, a plate plus speech therapy improved resting tongue and lip posture and feeding.30Boletim de Conjuntura (BOCA). PALATAL MEMORY PLATE IN TRISSOMY 21: BENEFITS OF EARLY INTERVENTION IN OROFACIAL DEVELOPMENT Widening the palate early improved tongue position, lip closure, drooling, and sucking.31Peirson Center. Early Palate Expansion for Kids with Down Syndrome A pediatric dentist or orthodontist with Down syndrome experience can say whether these suit your child.
At home, a therapist usually shows the family a few short exercises to repeat daily, since small regular practice matters more than long sessions. For young children the exercises become play, such as blowing bubbles, licking a treat from the lips, or games that call for closing the lips. Progress tends to be gradual over months, so the early weeks may not show much visible change. These studies were small, so results vary between children. Improvement means less time with the tongue out, not a changed face.
When Tongue Reduction Surgery Is Considered
Surgery to reduce the tongue is rarely needed and rarely performed in children generally.32PubMed. Tongue Reduction for Macroglossia In Down syndrome the tongue is relatively, not truly, large.33PubMed. Relative rather than absolute macroglossia in patients with Down syndrome: implications for treatment of obstructive sleep apnea Procedures that widen the mouth or lengthen the jaw tend to ease symptoms better than shrinking the tongue.34PubMed Central. Macroglossia in Beckwith-Wiedemann Syndrome Is Attributed to Skeletal Muscle Hyperplasia In a different condition, Beckwith-Wiedemann syndrome, the tongue really is overgrown and reduction remains the main treatment.35PubMed Central. Macroglossia in Beckwith-Wiedemann Syndrome Is Attributed to Skeletal Muscle Hyperplasia
It has still helped some children. In one group of seven children with Down syndrome and enlarged tongues, all ate and drank better after reduction, drooling stopped, and speech improved.36PubMed. Tongue reduction in children with Down’s syndrome; a functional operation In children overall the operation is fairly safe, though anesthesia can be tricky.37PubMed. Tongue Reduction for Macroglossia Doctors weigh the benefit against surgical risk, and therapy is usually tried first.
If surgery is being discussed, a few questions are worth asking. Is your child’s tongue truly enlarged, or is the real issue a small mouth? That changes which operation makes sense. Would work on the palate or jaw address the cause better than shrinking the tongue? How will breathing be managed during anesthesia, since children with Down syndrome can have narrower airways? And what changes in eating and speech should you expect afterward, and how long is recovery?
Cracked Lips and a Grooved Tongue
In one group of children with Down syndrome, about 78% had a fissured tongue, with deep grooves across the surface.38PubMed Central. Lip and oral lesions in children with Down syndrome. A controlled study And 64% had cracked lips and 38% had sore cracks at the mouth corners.39PubMed Central. Lip and oral lesions in children with Down syndrome. A controlled study Grooved tongue becomes more common with age.40Applied Sciences. Oral Manifestations in Children and Young Adults with Down Syndrome: A Systematic Review of the Literature A mouth held open dries out, leaving the lower lip chapped and cracked.41PubMed Central. Lip and oral lesions in children with Down syndrome. A controlled study
Grooves that are painless and look the same from week to week are typical for a fissured tongue and need no treatment. Burning or soreness, a bad smell, or white patches that don’t wipe away can point to an infection such as yeast and should be checked. Food and bacteria can collect in deep grooves, so gently brushing the tongue helps clear them.
Saliva pooling at the corners of an open mouth keeps the skin damp, and damp skin cracks. A lip balm and keeping the corners dry ease the cracks. Cracked corners can become infected with yeast or bacteria, so cracks that are red, crusted, or don’t heal deserve a visit to a doctor or dentist.