SNP Shot: Genomic Insights

Apert syndrome is a genetic condition marked by abnormalities in the skeleton. A defining characteristic is craniosynostosis, where the skull bones fuse prematurely. This early fusion hinders normal skull growth, impacting the shape of the head and face. Furthermore, individuals often exhibit syndactyly, the fusion of a variable number of fingers and toes.

Craniosynostosis is responsible for many of the distinctive facial features associated with Apert syndrome. The premature fusion restricts normal head growth, leading to midface hypoplasia (a sunken middle face), a beaked nose, a lined forehead, and sometimes a cleft palate (an opening in the roof of the mouth). An underdeveloped upper jaw can also cause dental issues, including missing teeth, irregular tooth enamel, and overcrowded teeth.

Vision problems are common in Apert syndrome due to eye abnormalities. These can include exophthalmos (bulging eyes), hypertelorism (widely spaced eyes), downslanting palpebral fissures (outside corners of the eyes that slant downward), strabismus (eyes that don't align), and ocular proptosis (shallow eye sockets). Some individuals also experience hearing loss or frequent ear infections due to malformed ear structures.

Abnormal development in the face and head can cause partial airway obstruction, leading to breathing difficulties. Furthermore, craniosynostosis can impact brain development, potentially affecting intellectual abilities, which can range from normal to mild or moderate intellectual disability.

Syndactyly, the fusion of fingers and toes, is a common feature. The severity varies, with the hands generally being more affected than the feet. Typically, three digits on each hand and foot are fused. In severe cases, all fingers and toes can be fused. Polydactyly (extra fingers or toes) occurs rarely. Bone abnormalities in the elbows or shoulders can also occur, restricting movement and impacting daily activities. These abnormalities may affect both sides of the body or only one.

Other possible signs and symptoms include hyperhidrosis (excessive sweating), oily skin with severe acne, or missing patches of hair in the eyebrows.

Inheritance:

Apert syndrome follows an autosomal dominant inheritance pattern. This means that only one copy of the altered gene in each cell is enough to cause the disorder. In most cases, the condition arises from new (de novo) mutations in the relevant gene. These mutations occur during the formation of eggs or sperm in a parent or in early embryonic development. These cases typically occur in families with no prior history of the disorder.