Idiopathic osteolysis denotes a group of rare bone disorders differentiated on the basis of clinical, radiological, and genetic criteria. Idiopathic multicentric osteolysis (IMO) is one form of osteolysis that can occur as an autosomal dominant condition. In childhood, affected individuals have arthritic-like episodes, followed by progressive deformities, radiological osteolytic changes, and variable degrees of disability. A peculiar face and variable renal involvement have been described as associated manifestations. We report on a family with three members affected by IMO in two generations showing variable bone changes and persistent proteinuria. A sporadic case with severe renal damage is also described in which a de novo dominant mutation is suggested. All patients had peculiar facial manifestations including triangular shape, protruding eyes, and micrognathia. These manifestations may be part of the syndrome of IMO.