Crouzon syndrome with acanthosis nigricans, also known as Crouzonodermoskeletal syndrome, is a genetic disorder that causes the skull bones to fuse too early in development (craniosynostosis) and skin abnormalities. The craniosynostosis causes changes to the shape of the head as well as unique facial features that may include wide-set eyes, a beaked nose, and a small upper jaw. The skin abnormalities seen in this condition are thick, dark and velvety areas (acanthosis nigricans) that occur in skin creases, such as the underarms and neck. Other features of this condition include subtle changes to the bones in the spine (vertebrae) that can be seen on x-ray as well as development of non-cancerous growths (cementomas) in the jaw.
Crouzon syndrome with acanthosis nigricans is caused by a change (mutation) in the FGFR3 gene and is inherited in an autosomal dominant way, which means a mutation in one of the two copies of the gene a person has is enough to cause the condition. The FGFR3 gene provides an instruction to the body to make a protein that signals bones to grow and fuse together. When there is a mutation in this gene, the protein is not made correctly, which causes the bones in the skull to fuse too early.
Crouzon syndrome with acanthosis nigricans is considered in a child who has craniosynostosis and acanthosis nigricans. A doctor may order head imaging, such as a CT or MRI, to look for clues of the condition. A skin doctor (dermatologist) may perform a skin exam. Genetic testing can be used to confirm the diagnosis. Surgery may be necessary to fix the skeletal abnormalities. If your child has been diagnosed with Crouzon syndrome with acanthosis nigricans, talk with their doctor about all current treatment options. Support groups are also a good source of information.