Some classes of distance-regular graphs (in particular, the graphs of alternating forms and of quadratic forms over the two-element field) in terms of fairly general regularity conditions and some forbidden subgraphs are characterized. Sveral theorems were presented in order to characterize the graphs. Unoriented graphs without loops and multiple edges were considered. A classification of graphs without crowns in which all the μ-subgraphs are regular graphs of diameter 2 with given positive degree Α was obtained.