CSTB and Alzheimer disease: For example, overexpression of the calcium-binding protein, S100B, causes LM deficits [39,40]; in cell systems, endostatin, a proteolytic product of collagen 18A1, inhibits neurite outgrowth [41]; and mutations in the protease inhibitor, cystatin B (CSTB), cause epilepsy and its deletion prevents the development of cognitive deficits in a model of AD [42,43].