Apert syndrome

Apert Syndrome, virtually synonymous with Acrocephalosyndactyly, is a branchial arch syndrome, characterized by a number of clinical features, resulting from a developmental anomaly. Specifically, this syndrome affects the first branchial (or pharyngeal) arch, which is the precursor of the maxilla and mandible. Since the branchial arches are important developmental features in a growing embryo, disturbances in its development create lasting and widespread effects. more...

Overview

In 1906, Eugène Apert, a French physician, first described nine people with a similar disorder. Since he was the first to do so, his name is associated with the syndrome.

Breaking down the name of this disorder, “acro” means “peak” in Greek and refers to the “peaked” hands of some people with this syndrome. Syndactyly refers to the webbing of fingers and toes.

What occurs in embryology is that hands and feet are supposed to have some selective cells die (known as selective cell death or apoptosis to separate the fingers and toes. In the case of acrocephalosyndactyly, selective cell death does not occur, and fusion of skin, and sometimes bone, between the fingers and toes occur.

As in Crouzon Syndrome, the bones of the skull are affected as well. Craniosynostosis results from the infant’s skull and facial bones fusing early while in development, disrupting normal bone growth. Fusion of different sutures lead to different patterns of growth of the skull. Examples include: trigonocephaly (fusion of the metopic suture), brachycephaly (fusion of the coronal suture), dolichocephaly (fusion of the sagittal suture), plagiocephaly (fusion of coronal and lambdoidal sutures), oxycephaly (fusion of most sutures).

Causes

There is some support that acrocephalosyndactyly occurs in an autosomal dominant mode, but the basic defect is still unknown. Evidence for this is that males and females are affected equally.

Nonetheless, almost all cases are sporadic, signifying that most are attributable to fresh mutations or an environmental insult to the genetic code. In 1995, A.O.M Wilkie, along with other researchers, published a paper showing evidence of a relationship between acrocephalosyndactyly and a gene, called Fibroblast Growth Factor Receptor 2, on chromosome 10.

There is also some evidence that the age of the father is related to this syndrome. This stands in stark contrast to Down Syndrome, where the age of the mother is positively correlated with the risk of having a child with the syndrome. It is speculated that older fathers are more likely to have mutations in the chromosomes of their sperm, but a correlation to this disorder has not been established through scientific research.

Symptoms

The cranial malformations are the most apparent effects of acrocephalosyndactyly. Cranial synostosis occurs, as explained above, with Brachiocephaly being the common pattern of growth. Additionally, a common characteristic is a high, prominent forehead and a flat posterior skull. Due to the premature closing of sutures of the skull, increased cranial pressure develops which sometimes leads to mental deficiency. Nonetheless, this is not always the case since some of these people possess normal intelligence. Furthermore, a flat or concave face may develop because of a deficient growth in the mid-facial bones, leading to a condition known as pseudomandibular prognathism. Other features of acrocephalosyndactyly may be shallow bony orbits and broadly spaced eyes.

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