Degenerations of the dog retina. II. Generalized progressive atrophy of hereditary origin.

A SPONTANEOUS degeneration of the retina of the dog, due to a generalized progressive atrophy of the neuroepithelium and called " night blindness " or retinitis pigmentosa of dogs has been known for nearly half a century, since Magnusson's recognition of the syndrome in Gordon Setters in Sweden about 1905 (Magnusson, 1909, 1911, 1917); he considered the condition to be similar to retinitis pigmentosa in man. More recently a somewhat similar syndrome has been reported in Red Irish Setters in England (Hodgman and others, 1949; Parry, 1951). These workers described in detail the clinical stages of the syndrome and presented evidence indicating that the disease was inherited as if determined principally by a recessive autosomal Mendelian factor. The present paper presents data obtained in a series of matings under controlled conditions designed to establish whether or not the syndrome is hereditary, to provide material for detailed histological and electrophysiological studies, and to establish the relationship of the canine syndrome to human retinitis pigmentosa.