Examination of an infant includes palpating the anterior fontanelle. Two smaller fontanelles are located on each side of the head, more anteriorly the sphenoidal or anterolateral fontanelle (between the sphenoid, parietal, temporal, and frontal bones) and more posteriorly the mastoid or posterolateral fontanelle (between the temporal, occipital, and parietal bones).During birth, fontanelles enable the bony plates of the skull to flex, allowing the childs head to pass through the birth canal. The ossification of the bones of the skull causes the anterior fontanelle to close over by 9 to 18 months. The sphenoidal and posterior fontanelles close during the first few months of life. The closures eventually form the sutures of the neurocranium. Other than the anterior and posterior fontanelles, the mastoid fontanelle and the sphenoidal fontanelle are also significant. Closure
In humans, the sequence of fontanelle closure is as follows:
The posterior fontanelle generally closes 2 to 3 months after birth;
The sphenoidal fontanelle is the next to close around 6 months after birth;
The mastoid fontanelle closes next from 6 to 18 months after birth; and
The anterior fontanelle is generally the last to close between 12 and 18 months. Clinical significance
The fontanelle may pulsate, and although the precise cause of this is not known, it is normal and seems to echo the heartbeat, perhaps via the arterial pulse within the brain vasculature, or in the meninges. This pulsating action is how the soft spot got its name – fontanelle is borrowed from the old French word fontenele, which is a diminutive of fontaine, meaning "spring".
Some infants are born with an opening in the roof of the mouth, which is called a cleft palate. Severe nearsightedness (high myopia) is sometimes present, as are other eye problems that can affect vision such as detached retinas. About one-quarter of people with this condition have mild to moderate hearing loss. Causes
Spondyloepiphyseal dysplasia congenita is one of a spectrum of skeletal disorders caused by mutations in the COL2A1 gene. The protein made by this gene forms type II collagen, a molecule found mostly in cartilage and in the clear gel that fills the eyeball (the vitreous). Type II collagen is essential for the normal development of bones and other connective tissues. Mutations in the COL2A1 gene interfere with the assembly of type II collagen molecules, which prevents bones from developing properly and causes the signs and symptoms of this condition.Spondyloepiphyseal dysplasia congenita is inherited in an autosomal dominant pattern, which means one copy of the altered gene is sufficient to cause the disorder. Management
There is no treatment for the underlying condition. Supportive/symptomatic treatment is based on the traits present in each person with the condition. Notable people
Michael Dunn, American actor, Tony winner, Wild Wild West, Star Trek
Warwick Davis, English actor and TV presenter

References
Spranger: Bone Dysplasias, Urban & Fischer 2002, ISBN 3-437-21430-6

Further reading
GeneReviews/NIH/NCBI/UW entry on X-Linked Spondyloepiphyseal Dysplasia Tarda
OMIM entries on X-Linked Spondyloepiphyseal Dysplasia Tarda


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