Craniosynostosis 

Introduction 

Craniosynostosis is a rare type of birth defect that affects the shape of a baby's skull 

The human skull

Many people think of the human skull as a single section of bone similar to the shell of an egg. However, the skull is more like a football – it consists of a number of plates of bone that fit together to create a sphere.

In between the plates of bone are strong elastic tissues called sutures. The sutures give the bone plates flexibility so the skull is able to grow along with the brain. This is important because the human brain grows rapidly following birth, literally doubling in size during the first three years of life, and the skull must grow to accommodate this growth.

After the skull and brain have grown to their full adult size, the sutures fuse together to create a single structure of bone. However, in cases of craniosynostosis, one or more sutures fuse together before birth or shortly afterwards.

Craniosynostosis is a rare skull problem that causes a baby to be born with, or develop, an abnormally shaped head.

The irregular skull shape in craniosynostosis can cause persistent headaches, learning difficulties, eye problems and other symptoms. Most symptoms develop in later childhood.

The symptoms of craniosynostosis usually result from increased pressure within the skull, which is called intracranial pressure (ICP).

Different types of craniosynostosis can be described based on the areas of the skull affected and the resulting changes in shape.

Read more about the symptoms and signs of craniosynostosis.

How is craniosynostosis diagnosed?

Craniosynostosis can usually be diagnosed by a paediatrician (specialist in treating children) after a visual examination of your baby's head.

Any severe distortions of the skull or face will be apparent, and the existence of ridges over fused sutures or misalignment of the ears also provide evidence of craniosynostosis.

An X-ray or CT scan of the skull may be taken to confirm a diagnosis. CT scans are usually only required to plan some types of surgery or if the diagnosis is in doubt.

If your child has other birth defects that suggest craniosynostosis may be part of a wider syndrome, a sample of their blood, hair or saliva may be taken and tested for any genetic mutations.

What causes craniosynostosis?

Craniosynostosis is the result of the premature fusion of different sections of the skull. This means the skull is unable to grow in affected areas.

When one area of the skull is prevented from growing, other areas may "overgrow" to compensate and limit the pressure developing around the brain. A lack of growth in some areas and compensatory growth in other areas will result in an altered head shape.

Craniosynostosis is usually classfied as either:

  • nonsyndromic – there are no other birth defects and the cause is unknown
  • syndromic – craniosynostosis is the result of one of several rare syndromes

A syndrome is a range of symptoms related to a common cause, which is usually – but not always – genetic.

How common is craniosynostosis?

Craniosynostosis is rare, affecting an estimated 1 in every 1,800 to 3,000 children. Three out of every four cases affect boys.

Nonsyndromic craniosynostosis is the most common form of the condition, accounting for 80-95% of all cases.

There are more than 150 different syndromes that can cause syndromic craniosynostosis, all of which are very rare. These include:

  • Apert syndrome – which affects 1 in every 100,000 children and disrupts the normal growth of bone before birth, resulting in deformities of the head, hands, feet and face
  • Crouzon syndrome – which affects 1 in every 60,000 children and disrupts the normal growth of bone in both the skull and the face, often resulting in severe facial disfigurement
  • Pfeiffer syndrome – which affects 1 in every 100,000 children and disrupts bone growth, resulting in deformities of the head and face; it also causes big toes, wide thumbs, and webbed hands and feet
  • Saethre-Chotzen – a genetic condition that affects around in 1 every 50,000 births and can cause a wide range of disfigurements, including facial defects

Treating craniosynostosis

The main treatment for craniosynostosis is surgery. This can either be carried out during the first year of your baby's life, or delayed until later childhood.

The timing of the surgery is decided by doctors, in consultation with you.

Most children with craniosynostosis recover well after surgery and the appearance of their skull improves significantly.

However, around 1 in 15 children may have further problems with their skull's development as they get older, which will require further surgery to correct.

Read more about treating craniosynostosis.

Page last reviewed: 03/11/2014

Next review due: 03/11/2016

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