| First Author | Schmalbruch H | Year | 1990 |
| Journal | Mouse Genome | Volume | 87 |
| Pages | 113 | Mgi Jnum | J:14295 |
| Mgi Id | MGI:62466 | Citation | Schmalbruch H, et al. (1990) 'Progressive motor neuropathy' (pmn), a new neurological mutant in the mouse. Mouse Genome 87:113 |
| abstractText | Full text of Mouse Genome contribution: PROGRESSIVE MOTOR NEURONOPATHY, (pmn), A NEW NEUROLOGICAL MUTANT IN THE MOUSE. This disease which is inherited in an autosomal-recessive fashion was found in a stock of mice (Pan:NMRI) at the Animal Department of the Panum Institute, Copenhagen. Heterozygotes are clinically normal. Homozygotes are identifiable 2-3 weeks after birth. Pelvic girdle and hindlimb muscles atrophy and become paralytic. Later also the forelimbs and the respiratory muscles are affected and all homozygotes die at age 6-7 weeks. They do not show other neurological symptoms. Skeletal muscles undergo denervation atrophy. The motor but not the sensory axons of the peripheral nerves degenerate. Axonal degeneration starts at the motor endplates and in a dying-back fashion progresses proximally. At 4-5 weeks all motor axons of the distal phrenic nerve have been lost; the number of myelinated axons is reduced by 70% (n=l2). The loss of fibres from the proximal part of the same phrenic nerves is only 55%. The loss of myelinated fibres in the peroneal nerve is 30% (n=9) and that in the sural nerve is 5% (n=9). The ventral root fibres of the lumbar spinal cord at 6 weeks are atrophic but not reduced in number. The anterior horn cells of the lumbar and cervical spinal cord appear light-microscopically normal; electron microscopy shows loss of rough endoplasmic reticulum but no other changes. Complete serial sectioning of the brain and brainstem (n=2) did not disclose any abnormalities. The spinal cord shows modest degeneration of the tractus gracilis (central axons of neurons of the dorsal root ganglia) and of a descending tract of the lateral funiculus (presumably reticulospinal) in terminally ill animals (age 6-7 weeks) only. Liver and kidney are histologically normal. The testes at 6 weeks show spermatogenesis but mature spermatozoa are not formed. This mutant for which we propose the name pmn and which might represent the first model for infantile spinal muscular in a small laboratory animal, has a rapidly progressive motor neuronopathy of the dying-back type. The short clinical course probably explains why no loss of anterior horn cells is seen. Henning Schmalbruch, Institute of Neurophysiology; Hans-Jorgen Skovgaard Jensen, Animal Department; THE PANUM INSTITUTE, University of Copenhagen, Denmark, Blegdamsvej 3c, DK 2200 Copenhagen N |
