Mouse Genome Informatics
hm
    Enpp1ttw/Enpp1ttw
involves: ICR
Key:
phenotype observed in females WTSI Wellcome Trust Sanger Institute
phenotype observed in males EuPh Europhenome
N normal phenotype
       
mortality/aging
• start to die around 18 weeks of age with most lost before 30 weeks of age

skeleton
• of the Achilles tendon
• changes are more pronounced and occur earlier in the superior spine than in the inferior spine (J:19124)
• at 8 weeks of age, rigidity of the vertebral column (J:37369)
• initially at 4 weeks of age, an amorphous calcifying lesion is detected protruding from the cartilaginous endplates into the fibrocartilage in the superior and inferior spine (J:19124)
• this lesion increases in size with age and degenerating or necrotic chondrocytes are seen around the lesion (J:19124)
• abnormal disks protrude into the spinal canaliculi or surrounding soft tissue and are associated with thickening of the osseous membranes and bone formation outside the degenerated calcified fibrous cartilage (J:19124)
• degeneration and destruction of the cartilage matrix with lateral protrusion (J:37369)
• disorganized proliferation of chondrocytes and irregular calcification in the protruded vertebral disks (J:37369)
• progressive dorsal and posterior protrusion of amorphous cartilaginous tissue from the posterior part of the intervertebral disk (J:43357)
• osteoblast-like cells are detected in the posterior intervertebral disks and the membrane surrounding the amorphous protruding tissue is progressively ossified (J:43357)
• deposition of calcium in the intervertebral spaces especially at the edges of the vertebral bodies
• calcified deposits can connect adjacent vertebral bodies similar to spur formation in osteoarthritis
• proliferation of fibrous tissue of the periosteum in areas over protruding intervertebral disks
• proliferation of cartilaginous tissues followed by endochondral ossification occurs around the site of tendon attachment and the around the osseous membrane (J:19124)
• at 10 weeks, proliferation of small fibroblast-like cells is seen at the site of ligament attachment and the posterior corner of the endplate (J:43357)
• moderate
• at 6 - 8 weeks , degeneration and necrosis of the chondrocytes with surrounding tidemarks of calcification are seen in the articular cartilage (J:19124)
• disorganized proliferation of chondrocytes in the protruded vertebral disks (J:37369)
• at 3 - 4 weeks, papillary proliferation of synovial cells protrude into the articular space (J:19124)
• at 6 - 8 weeks, cystic dilation of the articular sac, proliferation of synovial cells replacing articular cartilage, and some thicker collagen fibers with a longer periodicity are seen (J:19124)
• at 8 - 12 weeks, fibrosis of the synovial tissue is seen, proliferation is not as obvious, and the articular sac is fibrous and thickened with calcification and proliferation of the cartilaginous tissue (J:19124)
• around the site of tendon attachment osteophytes develop and after 20 weeks of age these may bridge the joint (J:19124)
• at 8 weeks of age, stiffness of limb joints (J:37369)
• at 4 weeks of age calcium deposits begin to accumulate (J:19124)
• at 6 - 8 weeks, calcium deposits are seen in the articular space and synovial tissue by 20 weeks of age the peripheral articular cartilage is replaced by bony tissue (J:19124)
• by 20 weeks of age the peripheral articular cartilage is replaced by bony tissue (J:19124)
• no pronounced deposition of calcium is seen in the kidneys (J:19124)
• in limb joints (J:37369)
• fibrous thickening of the ligaments around protruding intervertebral disks (J:19124)
• hypertrophy of the posterior longitudinal ligament in the cervical spine at 8 weeks of age (J:43357)
• at 10 weeks, proliferation of small fibroblast-like cells is seen at the site of ligament attachment in the spine (J:43357)
• osteoblast-like cells are detected in the posterior longitudinal ligament (J:43357)
• treatment with streptozotocin increases the area of ossification of the posterior longitudinal ligament (J:43357)
• erosion and destruction of limb joint articular cartilage with synovial cell proliferation but only occasional inflammation (J:37369)
• subchondral bone absorption beneath the joint surface (J:37369)
• deposition of calcium in the intervertebral spaces especially at the edges of the vertebral bodies (J:37369)
• irregular calcium deposits in areas over protruding intervertebral disks (J:37369)
• ossification of the membrane surrounding the abnormal amorphous tissue of the ligament enthesis (J:43357)

growth/size
• streptozotocin-treated mice do not show any increase in body weight compared to to untreated mice unlike in wild-type mice
• at 8 weeks of age, cease to gain weight

behavior/neurological
• impaired grasping ability at 3 - 4 weeks of age
• by 8 weeks of age mice appear to walk on tiptoes

cardiovascular system
• calcification of the aorta

homeostasis/metabolism
N
• serum calcium and phosphorus levels are similar to wild-type (J:19124)
• calcification of the hair follicles of the vibrissae, aorta, Achilles tendon, and limb joints
• serum alkaline phosphatase activity is increased at all ages tested and increases rather than decreases with age

immune system
• erosion and destruction of limb joint articular cartilage with synovial cell proliferation but only occasional inflammation (J:37369)
• subchondral bone absorption beneath the joint surface (J:37369)

muscle
• of the Achilles tendon

Mouse Models of Human Disease
OMIM IDRef(s)
Ossification of the Posterior Longitudinal Ligament of Spine; OPLL 602475 J:43357 , J:48527
Osteoarthritis Susceptibility 1; OS1 165720 J:19124 , J:37369
Spondyloarthropathy, Susceptibility to, 1; SPDA1 106300 J:37369