Hereditary hypotrophic axonopathy with neurofilament deficiency in a mutant strain of the Japanese quail.

A primary axonal disease affecting the central and peripheral nervous system was discovered in a new mutant strain of the Japanese quail, named quiver (Quv). Quv showed significantly smaller cross-sectional areas of the cervical spinal cord and the optic and sciatic nerves, when compared with controls by light microscopic morphometry. In the cervical spinal cord, electron microscopic morphometry indicated that myelinated axons in Quv were significantly smaller in size than in controls, though greater in density. The axonal circularity was not significantly different from that of controls. Electron microscopically and immunohistochemically, neurofilaments were not detected in the axons or neuronal cell bodies. Axons in Quv were composed mainly of microtubules, which were increased in number in relation to the axonal size. From these findings, the lesions observed in Quv were regarded as axonal hypotrophy (growth arrest or retardation) due to altered neurofilament expression.