Human mutations of GPNMB cause recessive and semi-dominant amyloidosis cutis dyschromica [18,63,64,65,66], a condition characterized by amyloid deposition in the papillary dermis; remarkably, though, the GPNMB protein is not a constituent of amyloid deposits [18]. The gene discussed is GPNMB; the disease is amyloidosis cutis dyschromia.