Apert syndrome

Background

Apert syndrome is a rare genetic condition characterised by abnormal craniofacial (skull and face) development and severe fusion of skin and bones between the individual fingers and toes.

Credits

Last updated October 2015 by Professor A Wilkie, Nuffield Professor of Pathology, Weatherall Institute of Molecular Medicine, Oxford University, Oxford, UK.

Although great care has been taken in the compilation and preparation of all entries to ensure accuracy, we cannot accept responsibility for any errors or omissions. Any medical information is provided is for education/information purposes and is not designed to replace medical advice by a qualified medical professional.

What are the symptoms?

The skull is made up of several flat, plate-like bones (cranial bones) connected by seam-like joints (sutures). These sutures allow neighbouring cranial bones to slide over each other during birth, and allow growth of the brain without restriction during childhood. The growth of the face involves similar sutures between the facial bones.

In Apert syndrome, cranial and facial sutures begin to fuse early (craniosynostosis). This early fusion alters the shape of the skull, which can raise pressure within the skull (intracranial pressure) and has consequences for development of the brain.

Children with Apert syndrome are also born with the skin and bones of the fingers and toes fused (syndactyly).

Common problems found in children with Apert syndrome include:

  • abnormal shaped head and face
  • malformations of the brain – these are usually fairly minor
  • increased pressure inside the skull (raised intracranial pressure)
  • cleft palate (see entry Cleft Lip and/or Palate)
  • prominence of the eyes. The eyes can be damaged if they cannot close fully
  • increased risk of ear infections, which can lead to hearing loss (see entry Deafness)
  • obstruction of the airways
  • dental problems related to wrongly positioned teeth
  • variable learning disability – usually mild to moderate

Problems with the heart and blood vessels, stomach, intestines, kidneys and genitals can also occasionally occur.

What are the causes?

Specific mutations in the FGFR2 gene cause Apert syndrome. This gene produces a protein that stimulates cells to develop as bone cells while the baby is developing in the womb. The mutation causes bone development to occur more rapidly than normal.

How is it diagnosed?

Apert syndrome is usually diagnosed by physical examination, paying particular attention to the combination of facial features and syndactyly of the fingers and toes. Associated craniosynostosis is investigated by X-rays and CT scanning, and genetic testing is used to identify the causative mutation in the FGFR2 gene.

How is it treated?

Treatment is given to improve symptoms and prevent complications. Early diagnosis can ensure that appropriate surgical intervention is carried out.

A child with Apert syndrome will need a coordinated programme of care, and will see a number of specialists including speech therapists, orthodontists, psychologists and ophthalmologists. In the UK a number of specialist craniofacial centres are funded to provide coordinated care for children with Apert syndrome.

Inheritance patterns and prenatal diagnosis

Inheritance patterns
Over 98% of cases arise from a new mutation; the risk for unaffected parents to have another affected child is well under 1%, if their own FGFR2 test is normal. An affected person has a 50% chance of passing the condition to each of their children.

Prenatal diagnosis
In high-risk pregnancies, prenatal diagnosis is available by chorionic villus sampling or amniocentesis, with specific testing of the FGFR2 gene. Preimplantation diagnosis would also be feasible. For lower risk pregnancies (for example, where neither partner is affected), careful ultrasound scanning from 12 weeks can provide reassurance that the baby is unlikely to have Apert syndrome. However, it should be noted that the routine 18 to 20 week scan offered to all pregnant women sometimes fails to detect the condition. Non-invasive prenatal diagnosis (NIPD) has recently become available by means of a maternal blood sample after 9 weeks of pregnancy.

Is there support?

Information and support in the UK for Apert syndrome is provided by Headlines (see entry Craniofacial conditions).

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