Apert's syndrome

Apert syndrome is a form of acrocephalosyndactyly, a congenital disorder characterized by malformations of the skull, face, hands and feet. It is classified as a branchial arch syndrome, affecting the first branchial (or pharyngeal) arch, the precursor of the maxilla and mandible. Disturbances in the development of the branchial arches in fetal development create lasting and widespread effects. In 1906, Eugène Apert, a French physician, described nine people sharing similar attributes and characteristics. Linguistically, in the term 'acrocephalosyndactyly', acro is Greek for 'peak', referring to the 'peaked' head that is common in the syndrome; cephalo, also from Greek, is a combining form meaning 'head'; syndactyly refers to webbing of fingers and toes. In embryology, the hands and feet have selective cells that die in a process called selective cell death, or apoptosis, causing separation of the digits. In the case of acrocephalosyndactyly, selective cell death does not occur and skin, and rarely bone, between the fingers and toes fuses. The cranial bones are affected as well, similar to Crouzon syndrome and Pfeiffer syndrome. Craniosynostosis occurs when the fetal skull and facial bones fuse too soon in utero, disrupting normal bone growth. Fusion of different sutures leads to different patterns of growth on the skull. Examples include: trigonocephaly (fusion of the metopic suture), brachycephaly (fusion of the coronal suture and lambdoid suture bilaterally), dolichocephaly (fusion of the sagittal suture), plagiocephaly (fusion of coronal and lambdoidal sutures unilaterally) and oxycephaly or turricephaly (fusion of coronal and lambdoid sutures). Findings for the incidence of the syndrome in the population have varied, with estimates as low as 1 birth in 200,000 provided and 160,000 given as an average by older studies. A study conducted in 1997, however, by the California Birth Defects Monitoring Program found an incidence rate of 1 in 80,645 out of almost 2.5 million live births. Another study conducted in 2002 by the Craniofacial Center, North Texas Hospital For Children, found a higher incidence of about 1 in 65,000 live births. The cranial malformations are the most apparent effects of acrocephalosyndactyly. Craniosynostosis occurs, in which the cranial sutures close too soon, though the child's brain is still growing and expanding. Brachycephaly is the common pattern of growth, where the coronal sutures close prematurely, preventing the skull from expanding frontward or backward and causing the brain to expand the skull to the sides and upwards. This results in another common characteristic, a high, prominent forehead with a flat back of the skull. Due to the premature closing of the coronal sutures, increased cranial pressure can develop, leading to mental deficiency. A flat or concave face may develop as a result of deficient growth in the mid-facial bones, leading to a condition known as pseudomandibular prognathism. Other features of acrocephalosyndactyly may include shallow bony orbits and broadly spaced eyes. Low-set ears are also a typical characteristic of branchial arch syndromes. All acrocephalosyndactyly syndromes show some level of limb anomalies, so it can be hard to tell them apart. However, the typical hand deformities in patients with Apert syndrome distinguish it from the other syndromes. The hands in patients with Apert syndrome always show four common features: