Summary:​ We show the value of genetic screening in 3 adults with limited phenotypes of three bone sclerosing genetic disease (GD):​ osteopetrosis (OPT), Camurati-Engelmann disease (CED) and pycnodysostosis.

Introduction:​ OPT, CED and pycnodysostosis are three rare bone diseases often diagnosed in childhood. However, some atypical phenotypes raise the problem of delayed diagnosis in adults. Genetic tests may then be useful to establish a formal diagnosis.

Methods:​ We report 3 cases of adult patients with symptomatic or asymptomatic bone sclerosing lesions for whom the clinical, radiological and biological explorations were atypical and did not allow a formal diagnosis. These unusual descriptions led to the search for genetic mutations.

Results:​ These 3 cases of limited phenotypes were associated with unknown or poorly described variants of 3 rare bone genetic diseases.

Conclusions:​ Genetic tests proved useful to establish the diagnosis and manage the condition of adults with rare bone sclerosing GD.