Retinal Neuropathology of Late Infantile Amaurotic Idiocy.

THE retinal histopathology of amaurotic idiocies, as seen in sections stained with routine technique, as well as some of the histochemical changes are relatively well known (Holmes and Paton, 1925; Givner and Roisin, 1944; MacMillan, 1948). Good knowledge of the neuropathology, however, in this group of diseases is largely limited to the brain (Spielmeyer, 1906). To demonstrate the changes of the ganglion cells, the neurites, dendrites, and the neuroglia of the retina in a typical case of late infantile amaurotic idiocy is the purpose of this paper. The late infantile type of familial amaurotic idiocy (Bielschowsky, 1913; Batten and Mayou, 1915) is one of a group of hereditary diseases characterized by neural lipid deposition and degeneration of neurons in the brain and retina. It is, strictly speaking, an early juvenile type of amaurotic idiocy (Elwyn, 1953; Frangois, 1961), and usually begins after the second year of life, presenting clinically with epileptic seizures, lack of mental development, weakness and ataxia, blindness, and death usually about 4 years after the first clinical signs. The fundus changes either closely resemble those of the juvenile type of amaurotic idiocy consisting of pigmentary changes and optic nerve atrophy or may exhibit lipoid ganglion cell degeneration resulting in a central cherry-red spot in addition to the pigmentary degeneration (Sorsby, 1958; Duke-Elder, 1940). The latter is described as rare by Duke-Elder (1940). The "cherry-red spot" does not have quite the same appearance as that seen in Tay-Sachs disease; it is less red due to the additional foveal pigment degeneration in the late infantile form and the surrounding white " halo " of swollen ganglion cells is less distinct due to atrophy of many of these cells. The basic pathology of all types of amaurotic idiocy is a slowly progressive deposition of prelipoid substances and so-called ganglioside (a phosphorus-free carbohydrate containing lipid) in ganglion cells of the brain and retina with subsequent degeneration of the fat-filled cells. In the retina the ganglion cell layer is involved in the infantile and late infantile types. Degenerative changes of the rods and cones combined with degeneration of the pigment epithelium leading to pigment migration and deposition in the retina-somewhat similar to that known from retinitis pigmentosa (Wolter, 1957)-are the basic pathology of the juvenile form and are also found in the late infantile type (Stock, 1908; Batten and Mayou, 1915; Holmes and Paton, 1925; Hagedoorn, 1940; Duke-Elder, 1941; Givner and Roisin, 1944; Elwyn, 1953; Franqois, 1961).