Phenotypes associated with this allele

• Allele Symbol: Myh4^tm1Lnwd
• Allele Name: targeted mutation 1, Leslie A Leinwand
• Allele ID: MGI:2183830
• Summary: 1 genotype

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Myh4^tm1Lnwd/Myh4^tm1Lnwd	involves: 129/Ola * 129P2/OlaHsd * C57BL/6	MGI:2450542

Genotype
MGI:2450542

hm1

• Allelic Composition: Myh4^tm1Lnwd/Myh4^tm1Lnwd
• Genetic Background: involves: 129/Ola * 129P2/OlaHsd * C57BL/6

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

Muscle abnormalities, such as increased muscle fiber size and interstitial fibrosis, in Myh1^tm1Lnwd/Myh1^tm1Lnwd and Myh4^tm1Lnwd/Myh4^tm1Lnwd mice

growth/size/body

decreased body weight ( J:44448 )

• by 100 days of age mutant mice weighed 20% less than heterozygous and wild-type littermates

muscle

abnormal skeletal muscle morphology ( J:44448 )

• increased spacing between muscle fibers

abnormal skeletal muscle fiber morphology ( J:78886 )

increased skeletal muscle fiber size ( J:44448 , J:78886 )

• increased mean fiber size (J:44448)

• increased cross sectional area (CSA) in all fiber types examined (J:78886)

decreased skeletal muscle fiber number ( J:78886 )

• decreased total fiber number in all hindlimb muscles

abnormal skeletal muscle fiber type ratio ( J:78886 )

• increased proportion of type IID fibers in gastrocnemius muscles

decreased skeletal muscle mass ( J:44448 , J:78284 , J:78886 )

• decreased gastrocnemius mass (J:44448)

• decreased vastus lateralis mass (J:44448)

• abnormal skeletal muscle mass and morphology were noted (J:78284)

• decreased muscle mass in tibialis anterior, gastrocnemius, and quadriceps muscles (J:78886)

skeletal muscle fiber atrophy ( J:78886 )

• fibers of gastrocnemic muscles show signs of severe atrophy and/or degeneration

impaired skeletal muscle contractility ( J:44448 )

• extensor digitorum longus muscles show reduced maximum tetanic force

muscle weakness ( J:44448 )

behavior/neurological

decreased grip strength ( J:44448 )

• decreased forelimb and hindlimb grip strength