The gene for X-linked Kallmann syndrome: a human neuronal migration defect

A new gene from the distal short arm of the human X chromosome has recently been cloned and characterized. Mutations in this gene lead to the neuronal migration defect observed in Kallmann syndrome. Although there is no direct proof for the involvement of this gene in neuronal migration, significant similarities between its predicted protein product and neural adhesion molecules have been found. X-linked Kallmann syndrome represents the first example in vertebrates of a neuronal migration defect for which the gene has been isolated.