SNP Shot: Genomic Insights

Crouzon syndrome with acanthosis nigricans is a genetic disorder characterized by craniosynostosis, where certain skull bones fuse prematurely during development. It also involves acanthosis nigricans, a skin condition.

The symptoms of Crouzon syndrome with acanthosis nigricans are similar to those of Crouzon syndrome. Both conditions involve the premature fusion of skull bones, affecting head and face shape. Common features include wide-set, bulging eyes due to shallow eye sockets, misaligned eyes (strabismus), a small, beaked nose, and a flat or sunken midface (midface hypoplasia). Less common features in both conditions are cleft palate, dental problems, and hearing loss. Individuals with either Crouzon syndrome or Crouzon syndrome with acanthosis nigricans typically have normal intelligence.

Crouzon syndrome with acanthosis nigricans is different from Crouzon syndrome due to the presence of skin abnormalities, specifically acanthosis nigricans. This condition causes thick, dark, velvety skin in folds and creases, such as the neck and underarms. Individuals with Crouzon syndrome with acanthosis nigricans may also have unique scars in these areas that are flat and pale, often from necessary surgeries. Furthermore, some affected individuals experience narrowed (choanal stenosis) or blocked (choanal atresia) nasal passages, leading to breathing difficulties. Hydrocephalus, a buildup of fluid in the brain, can also occur. Nasal passage issues and hydrocephalus are uncommon in Crouzon syndrome alone. Rarer features of Crouzon syndrome with acanthosis nigricans include minor spinal bone (vertebrae) changes, finger bone abnormalities, and non-cancerous jaw growths called cementomas.

Inheritance:

This condition follows an autosomal dominant inheritance pattern, meaning only one copy of the mutated gene is needed to cause the disorder. An affected individual may inherit the mutation from an affected parent. However, it more often arises from a new (de novo) mutation in the gene, occurring in individuals with no family history of the condition.