Retina in various animal models of neuronal ceroid-lipofuscinosis.

The childhood forms of human neuronal ceroid-lipofuscinosis (NCL) are invariably associated with a severe progressive retinopathy which commences at the photoreceptor level morphologically and proceeds to a final loss of neuronal cells accompanied by severe gliosis. In respective spontaneous animal conditions of NCL, in English setters, Dalmatian dogs, and New Zealand sheep, retinal involvement is not commensurate although the retina does not seem to be completely unaffected. In canine NCL, there might be functional and electro-physiological impairment of retinal cells, but retinal atrophy is not obvious. In ovine NCL, the retina, apart from accumulating NCL-specific lipopigments within neuronal perikarya, also shows loss of photoreceptors. Conversely, retinal pigment epithelial cells (RPE) in canine and ovine NCL contain peculiar lamellar inclusions, not seen in unaffected animals, possibly an indication of a disturbed phagocytic process of photoreceptor outer segments. Similar such lamellar inclusions have not been observed in RPE cells in human childhood NCL.