Mouse Genome Informatics
involves: 129S2/SvPas
phenotype observed in females
phenotype observed in males
N normal phenotype
• significant number of null mice are not born (14% versus the expected 25% born were null)

• occasionally clenched paws when suspended by the tail
• occasionally showed mild tremor
• significantly wider base and longer stride at 6 months of age suggesting a neuromuscular abnormality

• males weighed less than wild-type at all ages

• occasionally had widely placed hindpaws

reproductive system
• at 3 weeks of age, some seminiferous tubules showed premature germ cell loss from the epithelium and at 4 months of age, elongating/elongate spermatids and spermatocytes shed from the epithelium and entered the lumen of tubules in mutant testes

nervous system
• myelin foldings and recurrent loops were seen in myelin-forming Schwann cells of the sciatic nerve
• at 6 months of age, occasional degenerating axons were seen in sciatic nerve
• myelin outfolding (appeared as comma shaped extension of myelin and axoplasm), recurrent loops (appeared as one to five satellite myelinated axons around a larger myelinated axon), and myelin protruding into the axon were seen in sciatic nerves, quadriceps and saphenous nerves, predominantly at paranodal myelin
• number of fibers containing myelin outfoldings and loops increased progressively in sciatic nerves with age (from 1-6 months) as did the complexity of myelin outfoldings
• reduced nerve conduction velocities (30.8 m/s vs. 38.7 m/s in wild-type) and prolonged F-wave latencies

Mouse Models of Human Disease
Charcot-Marie-Tooth Disease, Type 4b1; CMT4B1 601382 J:94373