Fibrillin microfibrils are extracellular matrix structures composed primarily of the glycoprotein fibrillin, providing essential scaffolding for elastic fibre formation and tissue integrity. They play a critical role in maintaining the elasticity and strength of connective tissues, influencing organ function and mechanical resilience. Mutations affecting fibrillin microfibrils are central to Marfan syndrome, a disorder characterised by cardiovascular, ocular, and skeletal complications.