SNP Shot: Genomic Insights

Saethre-Chotzen syndrome is a genetic disorder characterized by craniosynostosis, the premature fusion of certain skull bones. This early fusion restricts normal skull growth, leading to alterations in the shape of the head and face.

In individuals with Saethre-Chotzen syndrome, premature fusion often occurs along the coronal suture, which extends across the top of the head from ear to ear. Other skull bones may also be malformed. These changes can result in an abnormally shaped head, a high forehead, a low hairline, droopy eyelids (ptosis), widely spaced eyes, and a wide nasal bridge. Facial asymmetry, where one side of the face appears different from the other, is also common. Characteristically, individuals with Saethre-Chotzen syndrome often have small, rounded ears.

The signs and symptoms of Saethre-Chotzen syndrome exhibit considerable variability, even among affected family members. Mild changes in the hands and feet may be present, such as webbing between the second and third fingers and a broad or duplicated big toe. While delayed development and learning difficulties have been reported, the majority of individuals with this condition possess normal intelligence. Less frequent signs and symptoms can include short stature, spinal abnormalities (vertebral defects), hearing loss, and congenital heart defects.

Robinow-Sorauf syndrome shares similarities with Saethre-Chotzen syndrome, including craniosynostosis and broad or duplicated great toes. Initially considered a distinct disorder, it has since been identified as a variant of Saethre-Chotzen syndrome, resulting from mutations in the same gene.

Inheritance:

Saethre-Chotzen syndrome follows an autosomal dominant inheritance pattern. This means that only one copy of the mutated gene in each cell is enough to cause the condition. An affected individual may inherit the mutation from a parent who also has the condition. However, in some cases, the mutation arises spontaneously in the affected individual, even if there is no family history of the disorder. Notably, some individuals carrying a TWIST1 mutation may not exhibit any apparent features of Saethre-Chotzen syndrome. Despite this, they still have a risk of passing the gene mutation onto their children, who could then develop craniosynostosis and other typical symptoms of the syndrome.