The Usher family tree, as described in "The Fall of the House of Usher", is peculiar due to its direct line of descent with minimal variation. This implies that the Ushers, similar to European nobility of previous centuries, are likely products of generations of incest. This lack of branching in the family tree has led to frail health and terminal illness, as seen in Roderick and Madeline Usher, the last of their lineage.

The ancestral curse in "The Fall of the House of Usher" is the result of the Usher family's incestuous practices. This inbreeding, indicated by the narrator's metaphor of a family tree without branches, has led to physical and mental deficiencies in Roderick and Madeline Usher. The story implies that their poor health and the ultimate collapse of the Usher house are consequences of this long-standing family curse.

Both the literal and symbolic House of Usher must be destroyed due to the degeneration of both the mansion and the Usher family line. The physical deterioration of the house mirrors the genetic decline of the family, resulting in conditions like Roderick's oversensitivity and Madeline's catalepsy. This destruction serves as a metaphor for the collapse of the Usher lineage and reflects Roderick's perception of a malevolent presence threatening their existence.

In "The House of Usher," Madeline and the widening fissure symbolize the genetic and mental degeneration of the Usher family. The fissure in the mansion represents the breakdown of the family line, paralleling Madeline's physical deterioration and Roderick's mental instability. This dual symbolism reflects the interconnectedness of their ailments, exemplifying Poe's use of double entendre, where both the family and the physical structure of the house are in decline.

It is not clear if Lady Madeline is real or a figment of Roderick Usher's imagination. It could be either. The narrator seems to believe that Madeline is real, but there are no other characters in the story who corroborate the narrator's account. The events surrounding Lady Madeleine's death and reappearance are similar to events in "The Fall of the House of Usher" and Poe's previous work, "Mad Trist", both stories which feature Poe's recurring themes of madness, decay, and death.

The ballad in "The Fall of the House of Usher" reflects the deteriorating state of both the Usher family and their mansion. It symbolizes the decline and eventual collapse of both the physical house and the mental state of its inhabitants, Roderick and Madeline Usher, linking their fate to the cursed lineage and the decaying structure they inhabit.

The collapse of the house in "The Fall of the House of Usher" symbolizes the demise of both the physical structure and the Usher family line. As the last members, Roderick and Madeline, die, the house's destruction mirrors the family's downfall. The storm and a mystical light highlight the connection between the house and its owners, illustrating the fall of the isolated aristocratic elite. The house's collapse into the tarn signifies the end of the Usher dynasty.