Saethre-Chotzen Syndrome Health Article

Demographics

Saetre-Chotzen syndrome affects both males and females equally. It most likely occurs in every racial and ethnic group. Approximately one or two in every 50,000 individuals has Saetre-Chotzen syndrome, making it the most common of the craniosynostosis syndromes.

Signs and symptoms

The cranium is made up of three main sections. The three sections are the face, the base of the cranium, and the top and sides of the head. Most of the cranium assumes its permanent shape before birth. However, the bones that make up the top and side of the head are not fixed in place, and the seams between the bones (cranial sutures) remain open. This allows the top of the head to adjust in shape, as the unborn baby passes through the narrow birth canal during labor. After birth, the cranial sutures will close, most often within the first few years of life. The shape of the cranium is then complete.

In Saethre-Chotzen, the shape of the cranium is abnormally formed. The reason is that the coronal suture closes too early, sometimes even before birth. The coronal suture separates the two frontal bones (forehead) from the parietal bones (top of the head). If the early closure is unilateral or asymmetric, then the forehead and face will form unevenly, from one side to the other. This also forces the top of the head to become more pointed, almost tower-like. The forehead looks high and wide. The face will appear uneven on each side, especially in the area of the eyes and cheeks.

There is also less space for the normal features of the face to develop. For instance, the eye sockets are more shallow, and the cheekbones are flat. This makes the eyes more prominent, and spaced further apart than normal. Adding to the unevenness of the face is drooping of the upper eyelids, and a slight down slant to the eyes. The nose may look beaked or bent slightly downward at the tip. In some individuals, the ears look small and lowset on the face.

The other main feature of the syndrome is minor abnormalities of the hands and feet. Webbing (syndactyly) commonly occurs between the second and third fingers and toes. The thumbs are short and flat. The fifth finger may be permanently curved or bent at the tip.

Each individual with Saetre-Chotzen is affected somewhat differently. The features are usually quite variable even within the same family. Most individuals are mildly affected. Their facial features may be somewhat flat and uneven, but not strikingly so. However, if more than one cranial suture closes too early (and this can happen in some individuals), there is more severe disfigurement to their face.

In addition to the physical characteristics, individuals with Saetre-Chotzen may have growth delays, leading to less than average adult height. Most individuals are of normal intelligence, although some may have mild to moderate mental retardation (IQ from 50-70). For the growth and mental delays, it becomes necessary to provide special assistance and anticipatory guidance.

Diagnosis

For many years, there was widespread discussion among physicians (geneticists) over whether a given patient would have either Saethre-Chotzen or Crouzon syndrome. There may even be confusion with other craniosynostosis syndromes or with isolated craniosynostosis. However, the availability of direct gene testing now allows for a more definitive diagnosis for these patients. Simply using a blood sample, a direct gene test for mutations in the TWIST gene can be done. If an individual also has mental retardation or other significant birth defects, it is suggested that they be screened more fully for deletions of the TWIST gene.

Treatment and management

Very often, the physical characteristics of Saethre-Chotzen are so mild that no surgical treatment is necessary. The facial appearance tends to improve as the child grows. However, sometimes surgery is needed to correct the early fusion of the cranial bones. A specialized craniofacial medical team, experienced with these types of patients, should do this surgery. Surgery may also be done to release the webbing of the fingers and toes.

Some of the more severely affected individuals with Saethre-Chotzen may experience problems with their vision. There may be less space in the eye socket due to the bone abnormalities of the face. This can lead to damage of the nerves of the eye and may require corrective surgery. The tear ducts of the eye can also be missing or abnormal. Re-constructive surgery is sometimes performed to correct the drooping of the eyelids or narrowing of the nasal passage.

Prognosis

Most individuals with Saethre-Chotzen syndrome appear to have a normal life span.