Apert Syndrome and Orthodontics UK

What is Apert syndrome?

Apert syndrome (acrocephalosyndactyly type I) is a rare autosomal dominant condition caused by specific mutations in the FGFR2 gene (most commonly p.Ser252Trp or p.Pro253Arg). It affects approximately 1 in 65,000 to 1 in 88,000 live births. The hallmark features are bicoronal craniosynostosis (premature fusion of both coronal sutures, producing a tower-shaped skull) and syndactyly of the hands and feet (fusion of digits). The craniofacial consequences are extensive: midfacial hypoplasia (the middle third of the face is significantly underdeveloped), shallow orbits producing exophthalmos (protruding eyes), a beaked nose, and severe maxillary retrusion. These craniofacial features drive the orthodontic problems that require management throughout childhood and into adulthood. Most patients require multiple surgical procedures across the first two decades of life, and orthodontic treatment is planned around this surgical schedule.

What dental and jaw problems does Apert syndrome cause?

The craniofacial anatomy of Apert syndrome produces several consistent dental and jaw problems. Severe Class III malocclusion — where the lower jaw protrudes relative to an underdeveloped upper jaw — is characteristic. The maxilla (upper jaw) is hypoplastic, set back, and narrow, while the mandible is typically of normal size, creating the reverse bite relationship. The palate is invariably high-arched and narrow; a full cleft of the hard and soft palate is present in a significant minority of patients. Teeth are frequently crowded in the narrow upper arch, with ectopic eruption patterns. Delayed dental eruption is reported across the dentition. Dental anomalies including supernumerary teeth, impacted teeth, and peg-shaped lateral incisors are more common than in the general population. The severe jaw discrepancy means that orthodontic treatment alone cannot achieve a functional occlusion — surgical correction of the midface and jaws is required.

How does sleep apnoea affect orthodontic planning in Apert syndrome?

Obstructive sleep apnoea (OSA) is one of the most clinically significant complications in Apert syndrome, occurring in the majority of affected children. Midfacial hypoplasia causes narrowing of the upper airway at multiple levels; the choanae (posterior nasal passages) may be stenotic, and the nasopharynx is reduced in volume. Severe OSA may require tracheostomy in infancy. Midface surgical advancement — Le Fort III osteotomy or frontofacial monobloc advancement — is often undertaken at least partly to improve the airway as well as for facial aesthetics. Orthodontic planning must account for the airway status: treatment timing, appliance selection, and the sequence of orthodontic preparation before jaw surgery are all influenced by the child's sleep study results and respiratory management. In children with a tracheostomy, orthodontic appliances must be compatible with tracheostomy care.

What is Le Fort III osteotomy and how does orthodontics fit around it?

Le Fort III osteotomy is a major craniofacial surgical procedure that separates and advances the entire midface — including the orbits, nose, and upper jaw — from the cranial base. It is one of the most significant surgical procedures in the management of Apert syndrome, typically performed in mid to late childhood (age 5 to 12 in many centres) primarily to protect the eyes from corneal exposure and to improve the airway, with facial aesthetics as a secondary goal. A second surgical stage — bimaxillary orthognathic surgery (Le Fort I and BSSO) — is usually planned after skeletal growth is complete (late teens to early twenties) to achieve final occlusal correction. Orthodontic treatment is required in two phases. Pre-surgical orthodontics aligns teeth within each arch (upper and lower independently) and decompensates the occlusion before final surgery. Post-surgical orthodontics fine-tunes the occlusion after the jaw bones are repositioned. Each surgical phase requires close collaboration between the orthodontist and the operating surgeon.

How does syndactyly affect oral hygiene and orthodontic appliance management?

Syndactyly — fusion of the fingers — is a defining feature of Apert syndrome. The degree of digital fusion varies but is typically severe, with fusion of at least the second, third, and fourth digits into a mitten-like hand in many cases. This has direct practical implications for dental care. Conventional toothbrushing is difficult or impossible with standard manual toothbrushes; electric toothbrushes with large handles, modified grip aids, or toothbrush holders may be required. Patients may need support from an occupational therapist to establish an effective oral hygiene routine. Removable orthodontic appliances — including clear aligners and removable retainers — are significantly harder to insert and remove with syndactylic hands. Fixed appliances are generally more appropriate as the primary orthodontic approach, as they do not depend on the patient's manual dexterity for insertion. Where removable elements are essential (for example, retainers after treatment), carers may need to be trained to assist.

What NHS pathway is available for children with Apert syndrome?

Children with Apert syndrome in the UK are managed through designated craniofacial units, which are concentrated in a small number of specialist centres. These include units at Great Ormond Street Hospital London, Birmingham Children's Hospital, Alder Hey Children's Hospital Liverpool, and a small number of other regional centres with established craniofacial teams. Referral is made at or shortly after diagnosis — often in the neonatal period — through the paediatrician, neonatologist, or clinical geneticist. The craniofacial team carries out neurosurgical, maxillofacial, ophthalmic, and orthodontic assessments and co-ordinates a longitudinal treatment plan. NHS funding covers specialist craniofacial surgery and orthodontic treatment within these designated centres. Parents should ask the paediatrician or GP to confirm referral to a designated craniofacial unit as early as possible.

What does orthodontic treatment involve across the lifespan in Apert syndrome?

Orthodontic involvement in Apert syndrome spans childhood, adolescence, and early adulthood. In early childhood, dental surveillance tracks eruption and identifies anomalies before intervention. In the mixed dentition, space management, alignment of ectopic teeth, and preparation of the arches for planned surgical stages begin. During the teenage years, pre-surgical orthodontics aligns and decompensates the arches before definitive bimaxillary surgery. Following final surgery in late adolescence or early adulthood, post-surgical orthodontics achieves final occlusal settling. Retention with fixed or removable retainers follows. Because the jaw surgery results in significant skeletal change, orthodontic tooth movements in the pre-surgical phase are counter-intuitive (intentionally worsening the bite temporarily to compensate for the surgical movement). This phase requires an experienced orthodontist familiar with orthognathic surgery mechanics and must be carried out in close coordination with the surgical team.

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This guide is for general information only. It is not a diagnosis, treatment plan, or substitute for advice from a registered dentist or orthodontist.