Introduction:

Pycnodysostosis is a rare disease secondary to a mutation in gen 1q21 that codifies the cathepsin K, proteolitic enzyme implicated in the metabolism of osteonectin, osteopontin and type I colagen. Its global incidence is around 1-1.7 cases per million, without genre prevalences, it is clinically caracterized by short stature, craneal deformities, «bird’s face» and bone fragility with pathological fractures tendency predominantly affecting long bones and occasionally vertebral pedicles. Radiologically is characterized by sclerous bones with permeable medular cannel. Despite there are numerous clinical reports on medical literature, just a litlle describe families with more than one afected member and its followship is usually short-term.

Objective:

To analize clinical evolution of these afected patients.

Material and methods:

A retrospective, descriptive, observational study was reelized in three patients with diagnosis of pycnodisostosis, between July 2006 and March 2016.

Results:

different affection forms of pycnodisostosis where observed, some of them, atipical, as for example spondilolisis and a escapule fracture in one patien.

Conclusions:

The present study could be the longest longitudinal report ever registered. By knowing the presented variety of manifestations and complications, the reader could select the best treatment method for each case.