Phenotypes Associated with This Genotype

Genotype
MGI:2175098

• Allelic Composition: Large1^myd/Large1^myd
• Genetic Background: MYD/Le-Os +/+ Large^myd/J

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

mortality/aging

premature death ( J:5670 )

• average life span 17.25 weeks, range 5-39 weeks

behavior/neurological

limb grasping ( J:5670 )

• involves hind limbs

• adduction of hind legs, flexion of the knee, ankles and toes

• severe contraction of hind limbs sometimes by 3-4 months of age

abnormal gait ( J:5670 )

• hind limbs held close to the body producing a short, shuffling gait

• hind limbs never extended and dragged

muscle

abnormal muscle morphology ( J:5670 )

abnormal skeletal muscle fiber morphology ( J:5670 )

• loss of striation

• central migration of nuclei

• nuclear "rowing"

increased variability of skeletal muscle fiber size ( J:5670 )

• variable fiber size

calcified muscle ( J:12034 )

• elevated calcium levels in skeletal muscles, particularly the diaphragm

• heart not affected

dystrophic muscle ( J:5670 )

muscle degeneration ( J:5670 )

abnormal muscle physiology ( J:5670 )

myositis ( J:5670 )

• mononuclear cell infiltration of areas surrounding degenerating fibers

myopathy ( J:5670 )

• diffuse and progressive myopathy

• widely distributed focal lesions in skeletal muscles as early as 16 days of age

nervous system

absent Schwann cells ( J:5974 )

• usually unmyelinated nerves lack Schwann cells but sometimes Schwann cells present but lacking myelin

abnormal spinal nerve morphology ( J:5974 )

• areas completely deficient in myelin

• not every root is affected

• observed in dorsal roots T13 to S1 and Ventral roots L1 to S1 (except L5)

• L3 and L4 ventral roots most severely affected

abnormal myelination ( J:5974 )

• areas where nerves are completely deficient in myelin

growth/size/body

abnormal tongue morphology ( J:5670 )

• musculature of tongue not affected until later

• subepithelial fibrosis in tongues of older mice

decreased body weight ( J:5670 )

• organ weights reduced comparably with reduced body weigh

postnatal growth retardation ( J:5670 )

• very severe at weaning

• growth improved after weaning but mice always small

skeleton

kyphosis ( J:5670 )

• thoracic kyphosis by 6-8 weeks of age

• becoming progressively worse with age

abnormal bone structure ( J:12034 )

• thinning of all bones examined

reproductive system

reduced fertility ( J:5670 )

• although not sterile, reproduction is very poor

immune system

myositis ( J:5670 )

• mononuclear cell infiltration of areas surrounding degenerating fibers

digestive/alimentary system

abnormal tongue morphology ( J:5670 )

• musculature of tongue not affected until later

• subepithelial fibrosis in tongues of older mice

craniofacial

abnormal tongue morphology ( J:5670 )

• musculature of tongue not affected until later

• subepithelial fibrosis in tongues of older mice