Nucleic acid sequence, amino acid sequence, replicative cloning vector, isolated host cell expression vector, methods for testing a substance as a therapeutic agent for bone modulation in a host to identify a molecule and a candidate protein involved in bone modulation, to test for hbm activity, for pharmaceutical development to treat bone development disorders, to treat a bone development disorder in an animal, to alter bone development in a host, to treat osteoporosis, to evaluate diagnosis for a genetic predisposition to a bone development disorder, to identify a genetic predisposition to bone development disorders, to express hbm protein in bone tissue, to amplify a nucleotide polymorphism, to identify a regulatory element of an hbm gene, and to modulate bone density and in one patient, diagnostic assay for bone development disorders, bacterial artificial chromosome, isolated nucleic acid segment, nucleic acid, and polypeptide.