Cone-rod dystrophy 1 (cord1) is a recessive condition that occurs naturally in miniature longhaired dachshunds (MLHDs). We mapped the cord1 locus to a region of canine chromosome CFA15 that is syntenic with a region of human chromosome 14 (HSA14q11.2) containing the retinitis pigmentosa GTPase regulator-interacting protein 1 (RPGRIP1) gene. Mutations in RPGRIP1 have been shown to cause Leber congenital amaurosis, a group of retinal dystrophies that represent the most common genetic causes of congenital visual impairment in infants and children. Using the newly available canine genome sequence we sequenced RPGRIP1 in affected and carrier MLHDs and identified a 44-nucleotide insertion in exon 2 that alters the reading frame and introduces a premature stop codon. All affected and carrier dogs within an extended inbred pedigree were homozygous and heterozygous, respectively, for the mutation. We conclude the mutation is responsible for cord1 and demonstrate that this canine disease is a valuable model for exploring disease mechanisms and potential therapies for human Leber congenital amaurosis.

Between 1990 and 1993, 16 cats were referred with acute onset blindness or intraocular haemorrhage. Blood pressure assessment, using the Doppler ultrasonic recording technique in 11 of the cats, proved these cases to be hypertensive. Fifteen cats underwent further investigation, revealing 13 with some degree of renal impairment and one as hyperthyroid. Five underwent cardiac ultrasound and all showed evidence of cardiac hypertrophy. The eyes from four of the cats were examined histologically and showed serous or haemorrhagic retinal detachments with varying degrees of retinal degeneration and a range of ocular hypertensive vascular changes. Two cats had full post mortem examinations which revealed evidence of renal and thyroid pathology.

Six horses with keratomycosis were examined and three different clinical expressions of the disease were recognised. The diagnostic work-up and response to treatment is described.

Two hundred consecutive referred cases of keratoconjunctivitis sicca in the dog were examined over a 9 year period. The clinical signs are described and the cases discussed in sections relating to the aetiology and in particular, the age and sex incidence in the West Highland White Terrier. The suitability of this animal as a model for Sjögrens syndrome in man is discussed.

A novel canine cone-rod dystrophy has been identified.

Three conditions of the cornea in the dog are described; a form of corneal dystrophy (central/paracentral lipid dystrophy, lipidosis, lipoidosis, cholesterolosis), degeneration (fatty and calcareous degeneration) and infiltration (arcus lipoides corneae, anterior embryotoxon, pre‐senile arcus). The clinical appearance, together with histopathological and ultrastructural details, are recorded. The age, sex, breed incidence and possible hereditary factors are also included. Reference is made to previous reports in the veterinary literature and the three conditions are compared with similar conditions in man.

Cataracts are a leading cause of blindness in both dogs and humans. Mutations in several genes have been associated with inherited forms of human cataract, but no mutations have been identified as the cause of any form of canine inherited cataract. We have used a candidate gene approach to investigate 20 genes, known to be associated with cataract in humans, for their potential association with the development of hereditary cataract (HC) in dogs. We have identified mutations in the HSF4 gene in Staffordshire Bull Terriers, Boston Terriers and Australian Shepherds affected by HC. Interestingly, different mutations in this single gene may be causing a recessive form of cataract in Staffordshire Bull Terriers and Boston Terriers and a dominant cataract in Australian Shepherds. Identification of the mutations that cause HC in these three breeds provides a method of controlling the disease within populations at risk using a simple diagnostic test, and also establishes cataract in these breeds as models for their human counterparts.

Primary lens luxation in the dog is encountered only in the terrier breeds and is typically a bilateral condition of both sexes arising in early to late middle age. The condition has recently appeared in the Tibetan Terrier and there is evidence to suggest an autosomal recessive mode of inheritance in this breed. In the majority of cases the dislocated lens passes forwards into the anterior chamber where its presence is likely to cause the development of acute glaucoma through obstruction of the pupil or filtration angle; for this reason lendectomy is the treatment of choice in such cases. Posterior luxations are less problematic but the approach to the treatment of subluxated lenses is controversial.