The autosomal dominant form of the disease (autosomal dominant osteopetrosis type 2 [ADO2]) is caused by single allele dominant negative mutations of the CLCN7 gene, encoding the ClC-7 chloride transporter indispensable for the mechanism of bone resorption.1 This evidence concerns the gene CLCN7 and Albers-Schönberg osteopetrosis.