AXIN2 gene

AXIN2

Mutations in the AXIN2 gene are often linked with oligodontia-colorectal cancer syndrome.  This syndrome causes colon and gastric polyps which may lead to an increased risk of colorectal cancer at an early age.  It is recommended that those who have a mutation in this gene get a colonoscopy every 2-3 years beginning between the ages of 25 and 30.  If polyps are found, frequency of colonoscopy should be increased to every 1-2 years and other options, such as surgical ones, should be considered.

In addition to the GI concerns, individuals with mutations in AXIN2 tend to have oligodontia which is defined as a person missing 6 or more permanent teeth. Individuals can also have sparse or no hair on their body including their scalp and face.

Inheritance

AXIN2 mutations are inherited in an autosomal dominant manner; therefore each child of a person with the mutation is at 50% risk for having inherited the disease causing mutation. Due to the variability of onset of polyposis, the patient’s siblings and their offspring may still be at risk for the condition.

Management

It is recommended that individuals with a pathogenic variant in AXIN2 undergo a genetics evaluation for features of oligodontia-colorectal cancer syndrome. Because the evidence regarding AXIN2 and colorectal cancer risk is limited and preliminary, there are no guidelines or recommendations to suggest alteration to medical management based solely on the presence of a pathogenic AXIN2 variant. However, an individual’s cancer risk and medical management are not determined by genetic test results alone. Overall cancer risk assessment incorporates additional factors, including personal medical history and family history, as well as available genetic information that may result in a personalized plan for cancer prevention and surveillance.

Knowing if a pathogenic variant is present is advantageous, even though the data regarding AXIN2 is currently limited. At-risk relatives can be identified, enabling pursuit of a diagnostic evaluation. Further, the available information regarding hereditary cancer susceptibility genes is constantly evolving and clinically relevant data are likely to become available in the near future. Awareness of this cancer predisposition encourages patients and their providers to be vigilant in maintaining close and regular contact with their local genetics clinic in anticipation of new information.

 

Gene Strength of Evidence Risk Status Association Reference

Resources

https://www.nccn.org/professionals/physician_gls/pdf/genetics_colon.pdf

Hereditary Colon Cancer Foundation 

PMID: 15042511, 21416598, 21626677

Lammi et al. - 2004 - Mutations in AXIN2 Cause Familial Tooth Agenesis and Predispose to Colorectal Cancer

Marvin et al. - 2011 - AXIN2-Associated Autosomal Dominant Ectodermal Dysplasia and Neoplastic Syndrome

Rivera et al. - 2014 - A novel AXIN2 germline variant associated with attenuated FAP without signs of oligodontia or ectodermal dysplasia

Lejeune Sophie et al. - 2006 - Low frequency of AXIN2 mutations and high frequency of MUTYH Mutations in Patients With Multiple Polyposis

Wong et al. - 2014 - Novel missense mutations in the AXIN2 gene associated with non-syndromic oligodontia