Phenotypes Associated with This Genotype

Genotype
MGI:3719609

• Allelic Composition: Tg(Myh6-Tnnt2)117Lnwd/0
• Genetic Background: involves: C57BL/6

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

cardiovascular system

abnormal myocardial fiber morphology ( J:48301 , J:56911 )

• neonatal and adult hearts show myocellular disorganization and degeneration (J:48301)

• cardiac myocytes show areas of focal myofibrillar lysis, misregistration of Z bands, and distinct regions of myofibrillar disarray (J:56911)

• however, cardiac fibrosis is rare, mice do not express markers of hypertrophy, mitochondrial structure is normal in myocytes, and no lipid deposition in myocytes is seen (J:56911)

decreased myocardial fiber number ( J:48301 )

• exhibit about 8-10% fewer myocytes than controls

decreased myocardial fiber size ( J:48301 )

• mean length and midpoint width of quiescent ventricular cardiac myocytes are 15 and 13% smaller, respectively, than in controls and mean myocyte area is decreased by 17%

myocardial fiber degeneration ( J:48301 , J:56911 )

• neonatal and adult hearts show myocellular degeneration (J:48301)

disorganized myocardium ( J:48301 )

• neonatal and adult hearts show myocellular disorganization

abnormal heart atrium morphology ( J:48301 )

• exhibit a small, but significant, increase in atrial size and atrial wall thickening

decreased heart weight ( J:48301 )

• heart weight to body weight ratio shows an 18-27% decrease in heart mass at 4-5 months of age, restricted to the left ventricle

decreased heart left ventricle weight ( J:48301 )

• exhibit a 17% decrease in left ventricular mass

abnormal cardiovascular system physiology ( J:48301 )

decreased cardiac muscle contractility ( J:48301 )

• altering the physiologic load on the heart shows some impairment in contractility

abnormal cardiac muscle relaxation ( J:48301 )

• at a baseline workload, hearts exhibit a 25% decrease in the maximal rate of relaxation

• hearts show a moderately good correlation of +dP/dT to increased work, however the slope of the Starling curve is severely decreased during relaxation suggesting that hearts cannot respond to an increased work load by shortening their relaxation time

abnormal myocardial fiber physiology ( J:48301 )

• isolated adult cardiac myocytes and hypersensitive to calcium; addition of calcium led to immediate cellular hypercontracture and death

muscle

abnormal myocardial fiber morphology ( J:48301 , J:56911 )

• neonatal and adult hearts show myocellular disorganization and degeneration (J:48301)

• cardiac myocytes show areas of focal myofibrillar lysis, misregistration of Z bands, and distinct regions of myofibrillar disarray (J:56911)

• however, cardiac fibrosis is rare, mice do not express markers of hypertrophy, mitochondrial structure is normal in myocytes, and no lipid deposition in myocytes is seen (J:56911)

decreased myocardial fiber number ( J:48301 )

• exhibit about 8-10% fewer myocytes than controls

decreased myocardial fiber size ( J:48301 )

• mean length and midpoint width of quiescent ventricular cardiac myocytes are 15 and 13% smaller, respectively, than in controls and mean myocyte area is decreased by 17%

myocardial fiber degeneration ( J:48301 , J:56911 )

• neonatal and adult hearts show myocellular degeneration (J:48301)

disorganized myocardium ( J:48301 )

• neonatal and adult hearts show myocellular disorganization

decreased cardiac muscle contractility ( J:48301 )

• altering the physiologic load on the heart shows some impairment in contractility

abnormal cardiac muscle relaxation ( J:48301 )

• at a baseline workload, hearts exhibit a 25% decrease in the maximal rate of relaxation

• hearts show a moderately good correlation of +dP/dT to increased work, however the slope of the Starling curve is severely decreased during relaxation suggesting that hearts cannot respond to an increased work load by shortening their relaxation time

abnormal Z line morphology ( J:56911 )

• misregistration of Z bands in cardiac myocytes

Mouse Models of Human Disease		DO ID	OMIM ID(s)	Ref(s)
hypertrophic cardiomyopathy 2		DOID:0110308	OMIM:115195	J:48301