Genetic Variant Screening of DNA Repair Genes in Myelodysplastic Syndrome Identifies a Novel Mutation in the <b><i>XRCC2</i></b> Gene

Abstract

Background: We aimed to detect single nucleotide polymorphisms (SNPs) and mutations in DNA repair genes and their possible association with myelodysplastic syndrome (MDS). Methods: Targeted enrichment resequencing of 84 DNA repair genes was initially performed on a screening cohort of MDS patients. Real-time polymerase chain reaction was used for genotyping selected SNPs in the validation cohort of patients. Results: A heterozygous frameshift mutation in the XRCC2 gene was identified. It leads to the formation of a truncated non-functional protein and decreased XRCC2 expression level. Decreased expression levels of all DNA repair genes functionally connected with mutated XRCC2 were also present. Moreover, a synonymous substitution in the PRKDC gene and 2 missense mutations in the SMUG1 and XRCC1 genes were also found. In the screening cohort, 6 candidate SNPs were associated with the tendency to develop MDS: rs4135113 (TDG, p = 0.03), rs12917 (MGMT, p = 0.003), rs2230641 (CCNH, p = 0.01), rs2228529 and rs2228526 (ERCC6, p = 0.04 and p = 0.03), and rs1799977 (MLH1, p = 0.04). In the validation cohort, only a polymorphism in MLH1 was significantly associated with development of MDS in patients with poor cytogenetics (p = 0.0004). Conclusion: Our study demonstrates that genetic variants are present in DNA repair genes of MDS patients and may be associated with susceptibility to MDS.

Noncoding RNAs and Their Response Predictive Value in Azacitidine-treated Patients With Myelodysplastic Syndrome and Acute Myeloid Leukemia With Myelodysplasia-related Changes

“…Regarding the DNA damage response, another pathway described in the context of the AZA response (18), we identified RAD51, BRCA1/2, and several members of the MCM gene family as core PCGs downregulated in the patients with future AZA failure. Alterations in RAD51 (36,69) and BRCA (70) genes have previously been reported in MDS. The expression of MCM genes, which are involved in the initiation and elongation phases of DNA replication, was reduced following epigenetic therapy (71).…”