Ultrastructural study of primary canine and human pigmentary retinopathy

Histopathologic study of autosomal dominant vitreoretinochoroidopathy. Peripheral annular pigmentary dystrophy of the retina

Autosomal dominant vitreoretinochoroidopathy (ADVIRC), a recently described disease, is clinically characterized by a slowly progressive or stationary circumferential peripheral pigmentary retinopathy with fibrillar condensation of the vitreous. Histopathologic study of an 88-year-old patient with this disease showed disorganization of the peripheral retina with focally atrophic retinal pigment epithelium (RPE). Altered pigment epithelial cells surrounded retinal blood vessels and lined the internal limiting membrane. At the equator, a remarkable and possibly unique multifocal loss of photoreceptor cells was seen. An extensive preretinal membrane, consisting of condensed vitreous with cellular debris and layers of Müller cells, was demonstrated by electron microscopic examination and immunohistochemistry. Histologically, this entity has some similarities to and some differences from retinitis pigmentosa. The clinical features are distinctive.

Morphological studies in canine (Dalmatian) neuronal ceroid-lipofuscinosis

Dalmatian dogs may develop a neuronal or generalized ceroid-lipofuscinosis (NCL) which strongly resembles that seen in English setters, especially as to the ultrastructural changes and ubiquity of the stored lipopigments and the retinal pathology, while differing clinically from the disorder of English setters in that the disease has a longer course of up to 5 or 6 yr. Clinical onset is at about age 6 months; however, an unequivocal morphological diagnosis is possible between the 4th and 5th month of life in biopsied skin. Detailed data of additional investigations are in progress and are awaiting later publication. Thus, NCL in the Dalmatian dog, though not yet as thoroughly investigated as NCL of the English setter, may provide another useful model for human NCL. Whether future biochemical studies will provide further similarities or even dissimilarities to NCL in English setters and in man remains to be seen. The cause of NCL in the canine and in humans is homozygosity of an autosomal recessive gene; however, the pathogenesis of the NCL in Dalmatian dogs is unknown as it is in English setters, other canine species, non-canine species, and in humans.