abnormal osteoblast differentiation impaired osteoblast differentiation csmith 2012-05-18T11:56:40Z MP:0011711 decreased osteoblast differentiation reduced ability or inability to produce skeletogenic cells that secrete osteoid, are capable of producing mineralized (hydroxyapatite) matrix, are located adjacent to or within osteoid tissue, and arise from the transformation of a preosteoblast cell MPheno.ontology