Members of the leucine-rich repeat family includes LRCH1, LRCH2, LRCH3 and LRCH4. All family members contain one calponin-homology domain and nine leucine-rich repeats. The best characterized leucine-rich repeat family member is LRCH4, which is suggested to be involved in ligand binding in the brain, with expression observed primarily in the hippocampus. As a cell adhesion molecule and signal receptor, LRCH4 may play an important role in maintenance of hippocampus-dependent memories, with defects in the gene possibly contributing to a loss of long-term memory. The gene encoding LRCH3 maps to human chromosome 3, which spans 200 million base pairs and encodes between 1,100 and 1,500 genes. There are three isoforms of LRCH3 that are produced as a result of alternative splicing events.