Pedigree analysis supports a correlation between an AXIN2 variant and polyposis/colorectal cancer

We present a patient with a history of colonic polyposis and family history significant for colon polyps and colorectal cancer (CRC). The patient and the family also had a history of bone loss of the jaw and early tooth loss, consistent with oligodontia. Genetic testing revealed the patient to have a previously unpublished variant of unknown significance (VUS) in the AXIN2 gene. These clinical findings have been demonstrated previously in only two other families, both of which exhibited oligodontia, colorectal neoplasia (polyps and cancer) and a heterozygous mutation in AXIN2. The AXIN2 protein is component of the Wnt pathway, which is known to be vital for organism development and cellular homeostasis. Alterations of the Wnt pathway lead to cell proliferation and neoplasm, in addition to agenesis of physical structures (such as teeth). The analysis of our pedigree further supports an association between colonic neoplasm (polyposis and CRC), the AXIN2 gene in general, and this particular VUS. It also highlights the importance of analyzing and disseminating information on pedigrees with less commonly encountered genomic abnormalities so that genotypic-phenotypic correlations can be solidified.