Leucine-rich repeat, immunoglobulin-like and transmembrane domains 1, or, LRIT1, is a human gene. Other names include: Leucine-rich repeat, immunoglobulin-like domain and transmembrane domain-containing protein 1; Leucine-rich repeat-containing protein 21; Photoreceptor-associated LRR superfamily protein; Retina-specific protein PAL; fibronectin type III, immunoglobulin and leucine rich repeat domains 9; FIGLER9; LRRC21. The encoded protein has an amino acid length of 623 and a mass of 68.0 kDa. Other isoforms may exist. This gene shares homology with other species, including: Mouse, Rat, Zebrafish.