Notably, TNSFR11A and TCIRG1 mutations are also reported in osteopetrosis, autosomal recessive 7 (OPTB7) and osteopetrosis, autosomal recessive 1 (OPTB1), respectively (Frattini et al., 2000; Guerrini et al., 2008; Pangrazio et al., 2012). This evidence concerns the gene TCIRG1 and osteopetrosis.