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Phenotypes Associated with This Genotype
Genotype
MGI:3613741
Allelic
Composition
Dmpktm1Rdd/Dmpk+
Genetic
Background
involves: 129S2/SvPas * C57BL/6J
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Dmpktm1Rdd mutation (0 available); any Dmpk mutation (37 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
muscle
• ultrastructurally, occasional skeletal muscle fibers display sarcomeric disorganization
• adult (7-11-month-old) heterozygotes display small diameter muscle fibers relative to wild-type mice
• adult (7-11-month-old) heterozygotes exhibit a variable reduction in tetanic force generation relative to wild-type mice
• adult (7-11-month-old) heterozygotes show increased skeletal muscle regenerative activity, as indicated by small increases in MyoD levels
• adult (7-11-month-old) heterozygotes display only a subtle, variable myopathy relative to age-matched homozygotes
• notably, heterozygous pups exhibit no overt symptoms of congenital myotonic dystrophy, including muscle hypotonia
• in addition, heterozygotes do not exhibit myotonia, which is a hallmark of the human disease

cardiovascular system
• adult heterozygotes exhibit a cardiac conduction defect (first-degree heart block), in the presence of normal intrinsic sinus node function
• similar to homozygotes, all adult heterozygotes display first-degree A-V block
• however, unlike homozygotes, adult heterozygotes display no higher-grade atrioventricular block
• prolonged mean P-R interval of 48 8 ms vs 34 5 in wild-type mice, but a normal P-wave duration and QRS interval

Mouse Models of Human Disease
DO ID OMIM ID(s) Ref(s)
myotonic dystrophy type 1 DOID:11722 OMIM:160900
J:53077


Contributing Projects:
Mouse Genome Database (MGD), Gene Expression Database (GXD), Mouse Models of Human Cancer database (MMHCdb) (formerly Mouse Tumor Biology (MTB)), Gene Ontology (GO)
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last database update
03/19/2024
MGI 6.23
The Jackson Laboratory