There were several characteristics and tendencies with which members of the Usher family were identified. Roderick Usher's ancestors had been known for
...a peculiar sensibility of temperament, displaying itself, through long ages, in many works of exalted art, and manifested, or late in repeated deed of munificent yet unobtrusive charity, as well as in a passionate devotion to the intricacies, perhaps even more than to the orthodox and easily recognizable beauties, of musical science...the stem of the Usher race, all time-honored as it was, had put forth, at no period, any enduring branch: in other words, that the entire famly lay in the direct line of descent, and had always, with very trifling and very temporary variations, so lain.
In addition, the mental condition from which Roderick suffers and has struck down his sister, Madeline, is apparently genetic and worsens with each generation. This mental disorder is the cause of the deaths of both Madeline and Roderick. Prior to his death, Roderick expresses his belief that the order of the stones comprising the walls of House of Usher are the cause of his family's downfall, as it "molded the destinies of his family, and ...made him what I now saw him."