Gerodermia　osteodysplastica　(GO)　is　a　segmental　progeroid　disorder　caused　by　loss-of-function　mutations　in　the　COMB　gene,　associated　with　early　onset　osteoporosis　and　bone　fragility.　A　conditional　mouse　model　of　GO　(GorabPnel)　was　generated　in　which　the　Gorab　gene　was　deleted　in　long　bones.　We　examined　the　biomechanical/functional　relevance　of　the　Gorab(Prx1)　mutants　as　a　premature　aging　model　by　characterizing　bone　composition,　tissue-level　strains,　and　whole-bone　morphology　and　mechanical　properties　of　the　tibia.　MicroCT　imaging　showed　that　GorabPnel　tibiae　had　an　increased　anterior　convex　curvature　and　decreased　cortical　cross-sectional　area,　cortical　thickness　and　moments　of　inertia,　compared　to　litter　mate　control　(LC)　tibiae.　Fourier　transform　infrared　(FTIR)　imaging　indicated　a　34%　decrease　in　mineral/matrix　ratio　and　a　27%　increase　in　acid　phosphate　content　in　the　posterior　metaphyseal　cortex　of　the　GorabPrx1　tibiae　(p　＜.05),　suggesting　delayed　mineralization.　In　vivo　strain　gauge　measurement　and　finite　element　analysis　showed　two　times　higher　tissue-level　strains　within　the　Gorab(Prx1)　tibiae　relative　to　LC　tibiae　when　subjected　to　axial　compressive　loads　of　the　same　magnitude.　Three-point　bending　tests　suggested　that　GorabPrx1　tibiae　were　weaker　and　more　brittle,　as　indicated　by　decreasing　whole-bone　strength　(46%),　stiffness　(55%),　work-to-fracture　(61%)　and　post-yield　displacement　(47%).　Many　of　these　morphological　and　biomechanical　characteristics　of　the　Gorab(Prx1)　tibia　recapitulated　changes　in　other　animal　models　of　skeletal　aging.　Future　studies　are　necessary　to　confirm　how　our　observations　might　guide　the　way　to　a　better　understanding　and　treatment　of　GO.　(C)　2017　Elsevier　Ltd.　All　rights　reserved.