Saethre-Chotzen syndrome (OMIM 101400) is an autosomal dominant genetic disorder associated with mutations mainly of the TWIST1 gene (7p21.1), and of the FGFR2 and FGFR3 genes. It usually manifests with unilateral or bilateral coronal synostosis and patients may have facial asymmetry, low frontal hairline, ptosis, strabismus and syndaktylia of fingers or toes, and the ears have a characteristic shape with a small flap. Also, patients may exhibit sensorineural or mixed hearing loss, short stature, congenital heart defects and vertebral column anomalies and hypertelorism. Intelligence is usually normal, but patients with deletions of the TWIST1 gene have a higher incidence of developmental delay.
In our laboratory we perform automated bi-directional fluorescent DNA sequencing of the entire coding region of the TWIST1 gene, as well as of exon 8 of the FGFR2 gene and of exon 7 of the FGFR3 gene. In parallel, we perform MLPA analysis to detect deletions of the TWIST1 gene region, which account for 7-10% of cases, thus allowing the detection of more than 80% of pathological mutations of the disease.