During development, genetically distinct subtypes of motor neurons express unique combinations of LIM-type homeodomain factors, which regulate cell migration and guide motor axons to establish the fidelity of a binary choice in axonal trajectory. The LIM gene family encodes a set of gene products, which carry the LIM domain, a unique cysteine-rich zinc-binding domain. At least 40 members of this family have been identified in vertebrates and invertebrates, and are distributed into 4 groups according to the number of LIM domains and to the presence of homeodomains and kinase domains. The human LHX5 gene maps to chromosome 12q23-q24 and encodes a 402 amino acid protein. The hippocampus contains the neural circuitry, which is crucial for cognitive functions such as learning and memory. LHX5 regulates precursor cell proliferation and neuronal differentiation and migration during hippocampal development.