Feature	Details
Origin	Isolated from human tissue (likely a natural recombinant of AAV1 and AAV2).
Primary Receptor	α-2,3 and α-2,6 N-linked Sialic Acid.
Secondary Receptor	HSPG (Heparan Sulfate Proteoglycan) — unlike AAV1.
Primary Tropism	Lung (Airway), Skeletal Muscle, Heart, Hematopoietic Stem Cells.
Clinical Focus	Airway diseases (Cystic Fibrosis), Duchenne Muscular Dystrophy (DMD).
Unique Trait	Highest cardiac efficiency among serotypes 1–9 in some models.
Seroprevalence	Moderate in humans (~30% to 45%).
The “K531” Factor	A single Lysine (K) at position 531 allows it to bind heparin, distinguishing it from AAV1.