Genetics Northern California

Apert Syndrome

Apert syndrome (also known as acrocephalosyndactyly type 1) is a rare condition affecting 15-16 per one million newborns. Newborns who have this syndrome are distinguishable by their abnormal skull shapes, syndactyly of the hands and feet, and specific facial features. Infants with Apert syndrome have craniosynostosis. This interferes with normal brain growth and will result in skull deformities. In addition, the midface (the area between the middle of the eye socket to the upper jaw) appears sunken and retruded. This is often referred to as midface hypoplasia. In about 30% of cases, cleft of the soft palate occurs. The hard palate is shorter than normal, but the soft palate is longer and thicker than normal. One of the most distinguishing features of Apert syndrome, however, is the fusing of the fingers and toes, in what is called syndactyly. The soft tissue between the second, middle, and ring fingers are often fused together. On occasion, the bones of the fingers will be fused as well. The thumb may be free, or it may be fused into the hand. The toes are affected similarly.

Children with Apert syndrome share the main features of the syndrome, including craniosynostosis, midface hypoplasia, and syndactyly of the hands and feet. These features contribute to abnormal skull growth, hearing loss, and difficulties eating and breathing. There are also less common findings in Apert syndrome that can vary from infant to infant. These include various heart defects, dextrorotation, pulmonary atresia, tracheoesophageal fistula, pyloric stenosis, polycystic kidneys, bicornate uterus, cervical fusions, hydrocephalus, ear infections, sleep apnea, severe acne, and an increased incidence of eye injuries. Attention should be paid to these features and they should be treated accordingly.

Cause
Apert syndrome can be the result of a genetic mutation or of sporadic occurrence. If genetics are involved, the likely candidate for mutation is the Fibroblast Growth Factor Receptor 2, which is located on Chromosome 10. The FGFR2 gene is responsible for bone growth. A mutation in a single base pair of DNA may be the source of Apert syndrome. There are cases, however, where genetics do not play a role in causing Apert sndrome. These cases may be the result of a new mutation where family histories do not indicate genetic inheritance.

Diagnosis
The diagnosis of Apert syndrome is made based on the clinical findings described in the definition above.

Treatment/Services
Treatment for Apert syndrome consists of surgeries to correct the craniosynostosis, the midface etrusion (through cosmetic reconstruction), the cleft palate (if necessary), and the fused hands and feet. Immediate and extensive evaluation by a skilled craniofacial team will reduce the negative consequences of the disorder and its features. Unfortunately, there is no treatment for the underlying disorder - the multidisciplinary approach offered by most craniofacial teams, however, will be comprehensive to adequately address the variety of the affected child's needs.

RESOURCES

Genetics Home Reference: Apert syndrome - General information about Apert syndrome provided by the National Library of Health. Also includes links to related sites.

The National Craniofacial Association: Apert Syndrome - Overview of Apert syndrome and list of resources.

A Guide To Understanding Apert Syndrome (pdf) - A parent booklet about Apert syndrome written by the Children's Craniofacial Association.