Table 1.

Classification of ‘idiopathic osteolysis’ according to Hardegger.

Type I	Multicentric osteolysis (+ carpotarsal)	Dominant trasmission	Infancy	Pain and edema in hands and feet
Type 2	Multicentric osteolysis (+ carpotarsal)	Recessive transmission	Infancy	Generalized osteoporosis
Type 3	Multicentric osteolysis (+carpo-metacarpal)	Non-hereditary	Infancy	Nephropaty
Type 4 (GSD)	Single center osteolysis	Non-hereditary	Aspecific (usually under 40)	Bone lymphatics
Type 5 (WC)	Monocentric osteolysis (+ carpotarsal)	Recessive autosomal	Infancy	Contractures, generalized osteoporosis and short stature

GSD, Gorham–Stout disease; WC, Winchester syndrome.