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mismatch repair deficiency
Also written as: MMR deficiency — mismatch repair deficiency
A cellular condition where DNA mismatch repair mechanisms are impaired, leading to accumulation of mutations.
Full Definition
A state in which the cellular machinery responsible for correcting DNA replication errors is non-functional, typically due to mutations in mismatch repair genes (MLH1, MSH2, MSH6, PMS2). This deficiency leads to a hypermutator phenotype with characteristic mutation signatures and microsatellite instability. Tumors with mismatch repair deficiency often respond well to immune checkpoint inhibitors due to their high neoantigen burden.
Usage
Usage note: Commonly abbreviated as dMMR (deficient) vs pMMR (proficient); ensure consistency with institutional style guides.
In Context
- "Immunohistochemistry confirmed mismatch repair deficiency with loss of MLH1 and PMS2 expression." — Pathology report
- "Patients with mismatch repair deficiency showed exceptional responses to pembrolizumab therapy." — Clinical trial manuscript
Also known as
MMR deficiency
dMMR
Contrasted with
mismatch repair proficiency
pMMR
Don't confuse with
microsatellite instability
DNA repair deficiency