Two patients with Apert syndrome with different mutations: the importance of early diagnosis

Cleft Palate in Apert Syndrome

Apert syndrome is a rare genetic disorder characterized by craniosynostosis, midface retrusion, and limb anomalies. Cleft palate occurs in a subset of Apert syndrome patients. Although the genetic causes underlying Apert syndrome have been identified, the downstream signaling pathways and cellular mechanisms responsible for cleft palate are still elusive. To find clues for the pathogenic mechanisms of palatal defects in Apert syndrome, we review the clinical characteristics of the palate in cases of Apert syndrome, the palatal phenotypes in mouse models, and the potential signaling mechanisms involved in palatal defects. In Apert syndrome patients, cleft of the soft palate is more frequent than of the hard palate. The length of the hard palate is decreased. Cleft palate is associated most commonly with the S252W variant of FGFR2. In addition to cleft palate, high-arched palate, lateral palatal swelling, or bifid uvula are common in Apert syndrome patients. Mouse models of Apert syndrome display palatal defects, providing valuable tools to understand the underlying mechanisms. The mutations in FGFR2 causing Apert syndrome may change a signaling network in epithelial–mesenchymal interactions during palatogenesis. Understanding the pathogenic mechanisms of palatal defects in Apert syndrome may shed light on potential novel therapeutic solutions.

Early Prenatal Ultrasound and Molecular Diagnosis of Apert Syndrome: Case Report with Postmortem CT-Scan and Chondral Plate Histology

Background Apert syndrome is characterized by craniosynostosis, midface hypoplasia and symmetric syndactyly. Case report: A 36-year-old mother, G2P1 underwent an ultrasound scan at 19 week's gestation. There was craniosynostosis, brachi-turricephaly and bilateral hand syndactyly. Genomic DNA from amniocentesis revealed the mutation C758C>Gp. (Pro to Arg substitution) at 252 of the exon 8 of the FGFR2 encoding for Apert syndrome. The pregnancy was terminated. Femoral chondral plate histology showed an increased interstitial matrix between bony trabeculae. Compared with normal, the trabeculae were thinner, more irregular with numerous osteoclasts suggesting abnormal bone remodeling. Hands and feet had an abrupt transition between resting and proliferating cartilage. Conclusion: Apert syndrome has increased intertrabecular matrix, thin trabeculae, increased remodeling, and irregular transition between the maturing and mineralization zones in the femur, and abnormal abrupt transition between the resting and proliferating cartilage in the fingers and toes.