An instance of double-strand break repair via nonhomologous end joining that is independent of factors important for V(D)J recombination (as opposed to classical nonhomologous end joining). It often results in a deletion with microhomology (i.e. 5-25bp homology) at the repair junction. Among different subclasses of nonhomologous end joining (NHEJ), alternative NHEJ appears to play a significant role in the etiology of mutations that arise during cancer development and treatment.
A-NHEJ