We introduce the class of deformed preprojective algebras of generalized Dynkin graphs A(n) (n >= 1), D-n (n >= 4), E-6, E-7, E-8 and L-n (n >= 1) and prove that it coincides with the class of all basic connected finite-dimensional self-injective algebras for which the inverse Nakayama shift nu(-1) S of every non-projective simple module S is isomorphic to its third syzygy Omega(3) S.