In isolated bone marrow cells from long bones of young (3 or 4 mo) and old (18 or 19 mo) mice, age correlated with reduced mRNA of mineral transport proteins: alkaline phosphatase (ALP), ankylosis (ANK), the Cl−/H+ exchanger ClC3, and matrix proteins collagen 1 (Col1) and osteocalcin (BGLAP). This evidence concerns the gene ANKH and ankylosis.