Sidekick-2 (SDK2), also known as KIAA1514, is a 2,172 amino acid single-pass type I membrane protein containing thirteen fibronectin type-III domains and six Ig-like C2-type (immunoglobulin-like) domains. Acting as a cell adhesion protein, Sidekick-2 guides axonal terminals to synapses in developing neurons. Sidekick-2 may require the interaction with MAGI scaffolding proteins for proper localization and function. Existing as four alternatively spliced isoforms, the gene encoding Sidekick-2 maps to human chromosome 17q25.1. Chromosome 17 makes up over 2.5% of the human genome with about 81 million bases encoding over 1,200 genes. Neurofibromatosis, a condition characterized by neural and epidermal lesions, and dysregulated Schwann cell growth have been linked to chromosome 17. Alexander disease, Birt-Hogg-Dube syndrome and Canavan disease are also associated with chromosome 17.