title: [Animal models for bone and joint disease. ttw (tiptoe walking), a model mouse of OPLL (ossification of the posterior longitudinal ligament of the spine)].
abstract: ttw (tiptoe walking), a known model mouse of OPLL (ossification of the posterior longitudinal ligament of the spine) is reviewed. ttw is a natural mutant which shows generalized ectopic calcification followed by ossification in the Achiles tendon, ear and spinal ligaments, etc. The trait is caused by a homozygous nonsense mutation in the gene for NPPS (nucleotide pyrophosphatase) , a cell-membrane enzyme that produces pyrophosphate. Its pathomechanism is the decrease of extracellular pyrophosphate due to insufficiency of NPPS. ttw is a excellent model for ectopic calcification and ossification. Several interesting genes related to ectopic calicification have been identified by studies using this mouse.
authors.affiliation: Laboratory for Bone and Joint Diseases, Center for Genomic Medicine, RIKEN.
authors.forename: Shiro
authors.initials: S
authors.lastname: Ikegawa
mesh_terms: D000818:Animals; D002114:Calcinosis / Q000235:genetics; D018389:Codon, Nonsense; D011756:Diphosphates / Q000378:metabolism; D004195:Disease Models, Animal; D005808:Genes, Recessive; D051379:Mice; D008817:Mice, Mutant Strains; D017887:Ossification of Posterior Longitudinal Ligament / Q000235:genetics / Q000473:pathology; D011755:Pyrophosphatases / Q000235:genetics* / Q000502:physiology
chemical_list: D018389:Codon, Nonsense; D011756:Diphosphates; D011755:Pyrophosphatases; C021899:nucleotide pyrophosphatase