Phenotypes Associated with This Genotype

Genotype
MGI:3625276

• Allelic Composition: Chkb^rmd/Chkb^rmd
• Genetic Background: involves: BALB/cByJ * C57BL/6J

• ♀: phenotype observed in females
• ♂: phenotype observed in males
• N: normal phenotype

Small size, radius and ulna deformities and muscle wasting in Chkb^rmd/Chkb^rmd mice

muscle

abnormal muscle fiber morphology ( J:108320 )

abnormal sarcolemma morphology ( J:108320 )

• increased numbers of subsarcolemmal vesicles are seen in the medial gastrocnemius muscle and multiple sites disruption are detected in the sarcolemma

• however, Evans blue dye indicates that sarcolemmal membrane integrity is normal

abnormal skeletal muscle fiber morphology ( J:108320 )

• enlarged mitochondria are seen in both hindlimb and forelimb muscles but no signs of mitochondrial proliferation are seen

centrally nucleated skeletal muscle fibers ( J:108320 )

• in hindlimbs 18% of fibers have centralized nuclei by 8 weeks of age compared to less than 2% of wild-type muscle fibers

dystrophic muscle ( J:108320 )

• at 66 days of age, hindlimb muscles display centralized nuclei, fatty infiltration, and loss of muscle fibers

• however, in forelimbs very little loss of muscle fibers is seen even at 1 year of age

• muscular dystrophy does not appear to affect lifespan

muscle degeneration ( J:108320 )

• at 66 days of age, forelimb muscles have variable fiber diameter and some centralized nuclei indicating degeneration and regeneration of muscle fibers

abnormal muscle physiology ( J:108320 )

limbs/digits/tail

abnormal forelimb morphology ( J:108320 )

• visibly rotated outward by 6 days of age

bowed radius ( J:108320 )

bowed ulna ( J:108320 )

• severely bowed

homeostasis/metabolism

abnormal enzyme/coenzyme level ( J:108320 )

• muscle creatine kinase levels are about 3-fold higher than in wild-type littermates

abnormal lipid level ( J:108320 )

• phosphatidylcholine levels are decreased in the forelimb muscles but not in the liver, brain, kidney , or heart

nervous system

nervous system phenotype ( J:108320 )

N • no abnormalities are seen in the spinal cord, sciatic nerves, retina, or neuromuscular junctions

skeleton

bowed radius ( J:108320 )

bowed ulna ( J:108320 )

• severely bowed

behavior/neurological

paraparesis ( J:108320 )

• hindlimb weakness

• significant loss of hindlimb motor control by 2-3 months of age; however only forelimb muscle is only slightly affected

Mouse Models of Human Disease		DO ID	OMIM ID(s)	Ref(s)
megaconial type congenital muscular dystrophy		DOID:0110632	OMIM:602541	J:108320