Single Suture Craniosynostoses: Physical traits

Fusion of the Suture:
What causes these sutures to fuse shut? We know that a number of factors can lead to early closure of a suture. The two most common causes for premature closure of a suture are genetic and environmental. For children affected with one of the single sutural closures, we currently believe that the most common cause is environmental. We know that it is possible to cause craniosynostosis in animals by restricting the skull from growing any larger while the animal is still in the womb. It is very likely that this is the primary cause for the majority of the single sutural synostoses. The uterus, or womb, is a relatively small space. We know that sometimes babies can end up in certain positions in the uterus where they cannot move around freely. One example would be those children who end up in a breech position, and can only be delivered by c-section. We theorize that children with a single sutural synostosis somehow end up positioned in the uterus so that there is pressure on the skull. This pressure can restrict the ability of the skull bones to be stretched apart by the growing brain. If the suture is not stretched apart, it "thinks" it's job is done and it fuses shut with normal bone. Abnormal skull shapes and single sutural synostosis is seen more commonly in twins than in single births, further supporting the theory of inutero constraint. It is also more common in boys than girls leading some researchers to speculate that testosterone might make suture closure more likely if there is any restriction of skull growth inside the uterus. Mothers who have delivered babies with single sutural synostosis should not feel guilty that they did anything wrong during their pregnancy to cause this condition. Craniosynostosis occurs in spite of the mother doing everything "right."

There are reports in the literature, and we have seen cases as well, of single sutural synostosis that are passed from generation to generation. This hereditary pattern suggests that the single sutural synostosis is caused by a problem with a gene and is being passed from one family member to the next. For example, a specific gene has been identified as causing plagiocephaly (unilateral coronal suture fused) in the same family, and this same gene has been identified in a small percentage of other children In spite of these rare occurrences, the overwhelming majority of single sutural synostoses appear to be the product of two parents with normal genes, and a mother who has normal prenatal care. When a child born with a single sutural synostosis grows up, and decides to have children, the chance of passing on the condition to his or her offspring is estimated to be less than 2%. If a couple has a child who is born with a single sutural synostosis, the chance of this couple having a another child with a single sutural synostosis is also thought to be about 2%.

Other common features of all single sutural synostoses:
Skull | Problems Caused by Sutural Fusion
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