In the context of T1D, damage-induced senescent beta cells show hallmarks of a persistent DNA damage response (DDR) involving Ser139 phosphorylated histone H2A.X (also called gamma-H2A.X) [69], which is typically elicited by the master kinase ataxia telangiectasia mutated (ATM) and marks double-strand breaks [92]. The gene discussed is ATM; the disease is type 1 diabetes mellitus.