homologous recombination deficiency
Also written as: HRD — homologous recombination deficiency
Impaired ability to repair DNA double-strand breaks through the homologous recombination pathway, creating therapeutic vulnerabilities.
Full Definition
A genomic instability phenotype resulting from defects in the homologous recombination DNA repair pathway, commonly due to BRCA1/BRCA2 mutations or other HR pathway gene alterations. This deficiency creates a characteristic genomic signature with large-scale copy number alterations and specific mutational patterns. Tumors with HR deficiency are particularly sensitive to PARP inhibitors and platinum-based chemotherapy due to synthetic lethality mechanisms.
Usage
Usage note: Often abbreviated as HRD; the term 'BRCAness' refers to a similar phenotype but should not be used interchangeably.
In Context
- "The HRD score of 42 indicated significant homologous recombination deficiency and predicted PARP inhibitor sensitivity." — Genomic testing report
- "Patients with homologous recombination deficiency showed improved progression-free survival on olaparib maintenance therapy." — Clinical trial results