[Autosomal dominant osteopetrosis: a presentation of 3 cases and a new gene mutation].

Osteopetrosis (OP) is a congenital bone disease which is caused by a functional disorder in osteoclasts with inability for normal bone resorption, leading to increased bone mineral density and bone sclerosis. It can be classified into different groups according to their clinical and their genetic characteristics: autosomal recessive with several subtypes (OPTB) or autosomal dominant type 1 or 2 (OPTA1-2). There is a wide clinical variability of the disease, from asymptomatic to lethal in the first months of life, with variable expressivity in the family members. Diagnosis is mainly clinical with genetic confirmation of the OP, and treatment is symptomatic. Three cases of OP are presented, with the discovery of a new gene mutation in LRP5 which caused OPTA1 in one of them.