Mouse Genome Informatics
hm1
    Mbnl1tm1Sws/Mbnl1tm1Sws
involves: 129S1/Sv * C57BL/6J
Key:
phenotype observed in females
phenotype observed in males
N normal phenotype
muscle
• splitting of myofibers
• no major degeneration was detected up to 11 weeks of age
• increased nuclei number and central position within myofiber
• myotonia noted in homozygotes beginning at 6 weeks of age
• delayed muscle relaxation was noticeable after a rest
• electromyographic recordings confirmed myotonic discharges

vision/eye
• mature cataracts seen at 8 months; progressive with age

Mouse Models of Human Disease
OMIM IDRef(s)
Myotonic Dystrophy 1; DM1 160900 J:86903


Mouse Genome Informatics
cn2
    Mbnl1tm1Sws/Mbnl1tm1Sws
Mbnl2tm1Sws/Mbnl2tm1Sws
Tg(Myog-cre)1Eno/0

involves: 129S1/Sv * 129S1/SvImJ * C57BL
Key:
phenotype observed in females
phenotype observed in males
N normal phenotype
growth/size/body

behavior/neurological
• develop severe motor deficits beginning at 12 weeks of age

skeleton
• develop kyphosis beginning at 12 weeks of age

muscle
• profound deficiency of adult skeletal muscle, with severe muscle pathology including small myofibers, fiber size heterogeneity, and centralized nuclei in nearly all myofibers


Mouse Genome Informatics
cx3
    Mbnl1tm1Sws/Mbnl1tm1Sws
Mbnl2tm1.1Sws/Mbnl2tm1.1Sws

involves: 129S1/Sv * 129S1/SvImJ * C57BL
Key:
phenotype observed in females
phenotype observed in males
N normal phenotype
mortality/aging
• time of lethality not specified


Mouse Genome Informatics
cx4
    Mbnl1tm1Sws/Mbnl1tm1Sws
Mbnl2tm1.1Sws/Mbnl2+

involves: 129S1/Sv * 129S1/SvImJ * C57BL
Key:
phenotype observed in females
phenotype observed in males
N normal phenotype
mortality/aging
• mice do not survive beyond 23 weeks of age

growth/size/body
• body weight is maintained at about 30% less than single Mbnl1 homozygotes

behavior/neurological
• 8-10 week old mice develop severe mobility problems
• 8-10 week old mice show impaired rotarod performance
• muscle weakness is seen as early as 4 weeks of age in the grip strength test

cardiovascular system
• hearts are enlarged and heart/body weight ratios are increased about 60%
• fibrosis is seen in enlarged right atria
• interstitial myocardial fibrosis
• PR interval is prolonged, indicating a first degree AV block

muscle
• increased muscle fiber size variation, atrophic and splitting fibers, and increased numbers of central nuclei indicative of muscle degeneration/regeneration are seen in muscles at 10-16 weeks of age
• myotonia is increased compared to single Mbnl1 homozygotes, with both the amplitude and duration of discharges increased 2.5 to about 4-fold
• however, the ejection fraction is not different from wild-type mice
• progressive muscle weakness and wasting

nervous system
• loss of mature neuromuscular junctions, and an increase in degenerated (fragmented endplates) and premature neuromuscular junctions in tibialis anterior muscles


Mouse Genome Informatics
cx5
    Mbnl1tm1Sws/Mbnl1+
Mbnl2tm1.1Sws/Mbnl2tm1.1Sws

involves: 129S1/Sv * 129S1/SvImJ * C57BL
Key:
phenotype observed in females
phenotype observed in males
N normal phenotype
mortality/aging
• reduction in embryonic viability