Handbook of Genetic Counseling/Craniosynostosis-1

< Handbook of Genetic Counseling




  • Craniosynostosis refers to the premature fusion of the cranial sutures (growth centers between the bones of the skull)
  • The skull is made up of a number of bones and when those bones fuse together too soon it doesn't allow the head to grow in the usual fashion and can lead to changes in head shape
  • Usually cranial sutures do not fuse completely until the fourth decade

Primary vs. secondary craniosynostosisEdit

  • Primary
  • suture growth is altered
  • head frequently assymmetric
  • the brain continues to grow in areas where sutures are open
  • most individuals are normal neurologically
  • benefit from surgery
  • Secondary
  • growth of brain is impaired
  • neurologically abnormal usually

Isolated vs. SyndromicEdit

  • Isolated
  • usually presents during first year of life
  • usually involves only one cranial suture (may involve more than one though)
  • no other associated abnormalities except those produced secondarily as a result of premature fusion of suture
  • sagittal suture is most common site for isolated craniosynostosis
  • suture that runs from front to back and separates parietal bones
  • results in head elongated from front to back due to limited growth laterally (scaphocephaly)
  • intracranial pressure is usually in the normal range
  • cranial surgery usually recommended to give a more usual head shape
  • usually babies with isolated craniosynostosis grow and develop normally
  • Syndromic
  • Other characteristic features present
  • over 60 syndromes described with craniosynostosis as a feature
  • bicoronal synostosis is the type present in the most common syndromes
  • Most follow AD inheritance
  • Most individuals with a craniosynostosis syndrome have normal intelligence
  • Saethre-Chotzen syndrome is the most common
  • characterized by facial asymmetry, low frontal hairline, ptosis, deviated nasal septum, brachydactyly, and partial cutaneous syndactyly of the toes
  • Crouzon - next most common (1 in 25,000 live births)
  • characterized by maxillary hypoplasia, shallow orbits, and ocular proptosis
  • Apert syndrome
  • characterized by strabismus, maxillary hypoplasia
  • complete symmetrical syndactyly of hands and feet
  • associated with risk for developmental delay (unlike most of the other AD craniosynostosis syndromes)
  • Pfeiffer syndrome
  • maxillary hypoplasia
  • broad thumbs and big toes
  • mild cutaneous syndactyly

Incidence of isolated nonsyndromic craniosynostosisEdit

  • 0.4-0.6 per 1000 births
  • so about 1 in 2000 births (Fetology, 2000)

Recurrence risks for isolated nonsyndromic craniosynostosisEdit

  • usually sporadic
  • genetic basis not discovered except for certain cases of unicoronal synostosis
  • In study of 125 patients with craniosynostosis only 2.5% of those with isolated synostosis had positive family history
  • patients with isolated craniosynostosis and a negative family history are not believed to have an increased incidence of recurrence above the background

Ultrasound detection of craniosynostosisEdit

  • difficult to detect on ultrasound
  • when it is detected it is often not until 3rd trimester
  • sometimes features associated with syndrome are detected on ultrasound (fused digits etc.)


  • objective is to allow adequate brain growth and improve appearance
  • Surgery for isolated craniosynostosis is usually a single operation and produces excellent cosmetic results in 93%



The information in this outline was last updated in 2003.