The MLH3 gene currently has no well-established disease association; however, there is preliminary evidence supporting a correlation with autosomal dominant Lynch syndrome (PMID: 11586295, 12702580).
Order this gene as a single gene test.
Invitae tests that include this gene:
MLH3 is a member of a group of DNA mismatch repair (MMR) genes. These genes encode proteins that detect and repair DNA mismatches that can occur during cell replication. The protein encoded by MLH3 functions as a heterodimer with MSH2. Somatic mutations in this gene frequently occur in tumors exhibiting microsatellite instability, and germline mutations have been linked to Lynch syndrome.
The MLH3 gene currently has no well-established disease association; however, there is preliminary evidence supporting a correlation with autosomal dominant Lynch syndrome (PMID: 11586295, 12702580). These data, however, are currently insufficient to make a clear determination regarding this association. Therefore, MLH3 is considered a “preliminary-evidence” gene and is available on Invitae’s Colorectal Cancer Panel. Preliminary-evidence genes are selected from an extensive review of the literature and expert recommendations, but the association between the gene and the specific condition has not been completely established. This uncertainty may be resolved as new information becomes available, and therefore clinicians may continue to order these preliminary-evidence genes.
MLH3 is one of several DNA mismatch repair (MMR) genes. These genes encode proteins that detect and repair DNA mismatches that can occur during cell replication. The protein encoded by MLH3 functions as a heterodimer with MSH2. Somatic mutations in this gene frequently occur in tumors exhibiting microsatellite instability, and germline mutations have been linked to Lynch syndrome (NCBI. Gene. Gene ID: 27030. http://www.ncbi.nlm.nih.gov/gene/27030. Accessed March 2018).
Variants in MLH3 have autosomal dominant inheritance. This means that an individual with a pathogenic variant has a 50% chance of passing that variant on to their offspring.
Because the evidence regarding MLH3 and Lynch syndrome is limited and preliminary, there are no guidelines or recommendations to suggest alteration to medical management based solely on the presence of a MLH3 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, family history, and any available genetic information that may result in a personalized plan for cancer prevention and surveillance.
Even though data regarding MLH3 are limited, knowing if a pathogenic variant is present is advantageous. At-risk relatives can be identified, allowing pursuit of a diagnostic evaluation. In addition, the available information regarding hereditary cancer susceptibility genes is constantly evolving and clinically relevant MLH3 data is likely to become available in the near future. Awareness of this variant encourages patients and their providers to inform at-risk family members, to consider implementing established screening protocols, and to be vigilant in maintaining close and regular contact with their local genetics clinic in anticipation of new information.
Review date: March 2018
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 in the transcript listed below. In addition, analysis covers the select non-coding variants specifically defined in the table below. Any variants that fall outside these regions are not analyzed. Any specific limitations in the analysis of these genes are also listed in the table below.
Based on validation study results, this assay achieves >99% analytical sensitivity and specificity for single nucleotide variants, insertions and deletions <15bp in length, and exon-level deletions and duplications. Invitae's methods also detect insertions and deletions larger than 15bp but smaller than a full exon but sensitivity for these may be marginally reduced. Invitae’s deletion/duplication analysis determines copy number at a single exon resolution at virtually all targeted exons. However, in rare situations, single-exon copy number events may not be analyzed due to inherent sequence properties or isolated reduction in data quality. Certain types of variants, such as structural rearrangements (e.g. inversions, gene conversion events, translocations, etc.) or variants embedded in sequence with complex architecture (e.g. short tandem repeats or segmental duplications), may not be detected. Additionally, it may not be possible to fully resolve certain details about variants, such as mosaicism, phasing, or mapping ambiguity. Unless explicitly guaranteed, sequence changes in the promoter, non-coding exons, and other non-coding regions are not covered by this assay. Please consult the test definition on our website for details regarding regions or types of variants that are covered or excluded for this test. This report reflects the analysis of an extracted genomic DNA sample. In very rare cases, (circulating hematolymphoid neoplasm, bone marrow transplant, recent blood transfusion) the analyzed DNA may not represent the patient's constitutional genome.
|Gene||Transcript reference||Sequencing analysis||Deletion/Duplication analysis|