Table 1.

Classification of “idiopathic osteolysis” according to Hardegger et al

Type	Typical age at manifestation	Location of the manifestation	Nephropathy	Prognosis
I Hereditary multicentric osteolysis with dominant inheritance	Juvenile	Carpotarsal osteolysis, sometimes affecting the radius and ulna	No	Good, self-limiting in adolescence
II Hereditary multicentric osteolysis with recessive transmission	Juvenile	Consistent with type I, in addition to generalized osteoporosis	No	Good, self-limiting in adolescence
III Nonhereditary multicentric osteolysis with nephropathy	Juvenile	Mainly carpometacarpal, tarsal involvement is rare, malignant hypertension	Yes, proteinuria in progressive renal pathology	Unfavorable
IV Gorham-Stout syndrome	Independent of age	Typical: shoulder, pelvis, facial skull bones	No	Usually good. When there is spinal involvement or chylothorax, mortality rises more than 50%
V Winchester syndrome (hereditary, autosomal recessive)	Juvenile	Carpotarsal osteolysis and contractures, short stature, osteoporosis, corneal deterioration	No	Progressive