Summary
The name osteopetrosis includes various inherited bone disorders characterized by a generalized skeletal densification due to a defective osteoclastic resorption. Mild autosomal recessive osteopetrosis is one of the 4 types of human osteopetrosis that have been clearly identified. It is extremely rare, with only 50 reported cases. It is marked by the classical triad: diffuse skeletal sclerosis, renal tubular acidosis and brain calcifications, but may sometimes include fractures after minimal trauma, failure to growth and/or mental retardation, and deformation of the limbs (especially genu valgum). The disorder is due to a mutation of the gene coding for carbonic anhydrase type II (CA II). The inherited absence of CA II explains the skeletal sclerosis (role of CA II in bone resorbing cells) and also renal tubular acidosis (tubular activity). Treatment is limited to general alcalinization. *Author: O. Benichou, M.D. (Sept. 2000)*
