Fibrillin-1 (FBN1) is a large extracellular matrix glycoprotein encoded by the *FBN1* gene, serving as a primary component of microfibrils that provide structural support and elasticity to connective tissues. These microfibrils also regulate signaling pathways, particularly TGF-β, by sequestering latent growth factors. Mutations in *FBN1* are linked to Marfan syndrome (MFS), a heritable disorder affecting the cardiovascular, skeletal, and ocular systems, as well as other fibrillinopathies like acromelic dysplasias. Antibodies targeting FBN1 are critical tools in research and diagnostics, enabling the visualization of microfibril architecture in tissues via immunohistochemistry (IHC) or immunofluorescence (IF). They also aid in detecting FBN1 expression levels in cell cultures or patient samples through Western blotting or ELISA, helping correlate protein abnormalities with clinical phenotypes. Additionally, FBN1 antibodies are used to study pathogenic mechanisms, such as disrupted microfibril assembly or dysregulated TGF-β signaling in MFS models. Commercially available monoclonal and polyclonal antibodies are typically validated against recombinant FBN1 fragments or epitope-mapped regions. Challenges include FBN1’s susceptibility to proteolysis and conformational complexity, requiring careful experimental optimization. Beyond basic research, FBN1 antibodies hold potential for therapeutic development, including antibody-based assays to monitor treatment efficacy in emerging therapies like angiotensin receptor blockers or gene-editing approaches for *FBN1* mutations.