Saethre-Chotzen syndrome occurs in about one in 25,000-50,000 births. It is inherited in an autosomal dominant fashion with variable expression. This means that roughly half of the children of a patient with Saethre-Chotzen syndrome can be expected to inherit the gene for the syndrome, but it may vary in severity or not show any signs in a person with the gene mutation. It is caused by a TWIST-1 gene mutation on chromosome 7p21. These patients typically have normal intelligence.
One sign of this syndrome is uneven appearance in the skull and facial features, even when both coronal sutures are closed. Between 50-75% of cases affect both coronal sutures, and 20-35% of cases have only one coronal suture closed. Most patients have a low hairline at the forehead.
These patients do not typically have the prominent appearance of the eyes seen with Crouzon, Apert or Pfeiffer syndromes because the eye sockets are almost normal size. In most cases, there is a drooping (ptosis) of the upper eyelids. Patients likely have a ridge of cartilage along the concha of the ear. The middle portion of the face usually grows to a normal size, but may be uneven. Some patients will have webbed fingers (syndactyly), which can be fixed by an experienced hand surgeon.
It is important to diagnose patients with Saethre-Chotzen and tell them apart from patients with non-syndromic craniosynostosis. About 40% of these patients will have very high pressure inside the skull after their initial skull expansion surgery. This can severely affect the brain’s health. Children with Saethre-Chotzen syndrome need to be followed closely by their craniofacial team until they are fully grown. About half of these patients will need two or more surgeries on the skull because the skull does not grow well.