TCIRG1 and osteosclerosis: T-cell immune regulator 1 (TCIRG1), also known as V-type proton atpase 116 kDa subunit a3 or T-cell immune response cDNA 7 protein (TIRC7), was first identified in osteosclerosis, and mutations in TCIRG1 are a common cause of human autosomal recessive osteosclerosis [22].