Base excision repair (BER) is a cellular process that fixes small, non-helix-distorting DNA lesions. These lesions can occur due to factors like oxidative stress or spontaneous chemical changes. The repair mechanism begins with specific enzymes called DNA glycosylases, which recognize and remove the damaged base, creating an abasic site. Once the damaged base is removed, other enzymes, including AP endonucleases and DNA polymerases, step in to fill the gap. The final steps involve sealing the DNA strand with DNA ligases, ensuring the integrity of the genetic material is restored. This repair pathway is crucial for maintaining genomic stability.