Phenotypes Associated with This Genotype

Genotype
MGI:8270636

• Allelic Composition: Dmd^em1Rcn/Y
• Genetic Background: C57BL/6J-Dmd^em1Rcn

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

muscle

increased cardiac muscle contractility ( J:296560 )

♂ • ejection fraction and fractional shortening are increased by 22% and 36% respectively

decreased skeletal muscle fiber size ( J:296560 )

♂ • myofibers in gastrocnemius and triceps are more heterogenous and smaller in size

♂ • on average, there is a 28% and 32% decrease in myofiber size in the gastrocnemius and triceps, respectively, at 54 weeks of age, but not in the diaphragm

♂ • however, no difference in the average minimum Ferets diameter is seen in skeletal muscle

centrally nucleated skeletal muscle fibers ( J:296560 )

♂ • in gastrocnemius, triceps, and diaphragm from 12-week-old mice, 60%, 69%, and 52% of myofibers contain centralized nuclei, respectively

♂ • in gastrocnemius, triceps, and diaphragm from 52-week-old mice, 57%, 60%, and 45% of myofibers contain centralized nuclei, respectively

skeletal muscle atrophy ( J:296560 )

♂

skeletal muscle degeneration ( J:296560 )

♂ • increase in muscle turnover in the gastrocnemius and triceps but not in the diaphragm is seen at 12 weeks of age and at 52 weeks of age indicative of excessive muscle degeneration

skeletal muscle fibrosis ( J:296560 )

♂ • increase in fibrosis in gastrocnemius, triceps, diaphragm, and heart tissue by 2.9-, 3.6-, 2.4-, and 3.8-fold, respectively

♂ • 2-fold increase in fibrosis in the diaphragm at 52 weeks compared to 12 weeks of age

skeletal muscle necrosis ( J:296560 )

♂

dystrophic muscle ( J:296560 )

♂ • mice develop progressive muscular dystrophy

cardiovascular system

cardiac hypertrophy ( J:296560 )

♂ • cardiomyocytes show increased cell surface area of approximately 1.4-fold at both 12 and 52 weeks of age, indicating cardiac hypertrophy

♂ • muscle histology shows that pseudohypertrophy is primarily attributed to fibrotic development

increased cardiac muscle contractility ( J:296560 )

♂ • ejection fraction and fractional shortening are increased by 22% and 36% respectively

abnormal heart echocardiography feature ( J:296560 )

♂ • echocardiography shows that during systole and diastole, a 15-25% and 8-21% increase in posterior wall thickness occurs, respectively, a reduction in chamber systolic volume by 41% and diastolic volume by 22%, and reduced ventricular diameter by 19% during systole and 9% during diastole, indicating a constrictive hypertrophic response

increased heart rate ( J:296560 )

♂ • heart rate is increased by 22%, 17%, and 27% at 12-, 28-, and 52-weeks of age, indicating consistent tachycardia

behavior/neurological

decreased grip strength ( J:296560 )

♂ • mice show weakened muscle strength from 12 to 52 weeks of age, where there is decreased grip strength by 20-30%

growth/size/body

cardiac hypertrophy ( J:296560 )

♂ • cardiomyocytes show increased cell surface area of approximately 1.4-fold at both 12 and 52 weeks of age, indicating cardiac hypertrophy

♂ • muscle histology shows that pseudohypertrophy is primarily attributed to fibrotic development

increased body weight ( J:296560 )

♂ • heavier body weight at 12 and 52 weeks of age

homeostasis/metabolism

increased circulating creatine kinase level ( J:296560 )

♂ • serum creatine kinase level is elevated approximately 1.7-fold at both 12 and 52 weeks of age

abnormal response to exercise ( J:376007 )

♂ • mice exhibit higher number of damaged fibers after the treadmill regimen indicating increased exercise-induced muscle damage

♂ • mice show no increase in tetanic force after exercise as is seen in wild-type mice

Mouse Models of Human Disease		DO ID	OMIM ID(s)	Ref(s)
Duchenne muscular dystrophy		DOID:11723	OMIM:310200	J:296560