This test analyzes the AXIN2 gene, which is associated with oligodontia-colorectal cancer syndrome. Individuals with this condition present with oligodontia (defined as congenital agenesis of six or more permanent teeth) in childhood followed by an increased risk of colorectal cancer in adulthood.
Analysis of this gene may confirm a diagnosis and help guide treatment and management decisions. Identification of a disease-causing variant would also guide testing and diagnosis of at-risk relatives. This test is specifically designed for heritable germline mutations and is not appropriate for the detection of somatic mutations in tumor tissue.
AXIN2 can also be ordered as part of a larger panel to test for different types of hereditary cancer conditions. Depending on the individual’s clinical and family history, one of these larger panels may be appropriate. Any of these larger panels can be ordered at no additional charge.
Oligodontia-colorectal cancer syndrome
The AXIN2 gene is essential for the development of permanent teeth. Oligodontia, defined as the congenital agenesis of six or more permanent teeth, is relatively rare. It can occur in isolation but is most often associated with other congenital anomalies. Pathogenic variants AXIN2 are known to cause oligodontia. Recent evidence has also found that individuals with such variants are also predisposed to developing colon adenomas, polyps, and colorectal cancer. This condition is called oligodontia-colorectal cancer syndrome. Affected individuals may present with oligodontia and/or colorectal cancer; the risks for each is currently unclear.
Individuals with a pathogenic variant in AXIN2 have an increased risk of malignancy compared to the average person. However, not everyone with such a variant will actually develop cancer. Further, the same variant can present differently, even among family members. Because we cannot predict which cancers may develop, most who are found to have a pathogenic variant will be offered screening tests to detect and prevent cancer. The precise colorectal cancer risks associated with AXIN2 pathogenic variants is currently unknown because the number of reported cases is limited.
Oligodontia-colorectal cancer syndrome is inherited in an autosomal dominant pattern.
The prevalence of oligodontia-colorectal cancer syndrome is currently unknown.
Invitae is a College of American Pathologists (CAP)-accredited and Clinical Laboratory Improvement Amendments (CLIA)-certified clinical diagnostic laboratory performing full-gene sequencing and deletion/duplication analysis using next-generation sequencing technology (NGS).
Our sequence analysis covers clinically important regions of each gene, including coding exons, +/- 10 base pairs of adjacent intronic sequence, and select noncoding variants. Our assay provides a Q30 quality-adjusted mean coverage depth of 350x (50x minimum, or supplemented with additional analysis). Variants classified as pathogenic or likely pathogenic are confirmed with orthogonal methods, except individual variants that have high quality scores and previously validated in at least ten unrelated samples.
Our analysis detects most intragenic deletions and duplications at single exon resolution. However, in rare situations, single-exon copy number events may not be analyzed due to inherent sequence properties or isolated reduction in data quality. If you are requesting the detection of a specific single-exon copy number variation, please contact Client Services before placing your order.
|Gene||Transcript reference||Sequencing analysis||Deletion/Duplication analysis|