FREM1 is a 2,179 amino acid protein that contains one C-type lectin domain, one Calx-beta domain and twelve CSPG repeats. Localized to the basement membrane of embryonic epidermal cells and secreted into extracellular space, FREM1 functions as an extracellular matrix protein that is essential for epidermal adhesion during embryogenesis and may also participate in epidermal differentiation. FREM1 exists as multiple alternatively spliced isoforms and is encoded by a gene which maps to human chromosome 9. Chromosome 9 contains 145 million base pairs and comprises 4% of the human genome, encoding nearly 900 genes. Hereditary hemorrhagic telangiectasia, which is characterized by harmful vascular defects, and Familial dysautonomia, are both associated with chromosome 9. Notably, chromosome 9 encompasses the largest interferon family gene cluster.