Renal disease affecting 3 male and 1 female English Cocker Spaniels was studied. Clinical features of the disease included proteinuria and progressive deterioration of renal function. Dogs were 11 to 27 months old when euthanized because of severe chronic renal failure. Grossly, the renal cortices were thin. Light microscopic evaluation revealed diffuse glomerular disease characterized by mesangial thickening, glomerular fibrosis, periglomerular fibrosis, and glomerular obsolescence. Based on these clinical and pathologic features, familial nephropathy of English Cocker Spaniels was suspected despite the fact that the individual dogs were not closely related. On transmission electron microscopy, a distinctive ultrastructural lesion was observed escriptions of renal disease in young Cocker Spaniels D have appeared intermittently for more than 35 years.Reduced thickness of the renal cortex of both kidneys was observed in young dogs with severe renal failure, and the condition was first called renal cortical hypoplasia in reports from Sweden,'.' Switzerland,' and Australia.4 Early investigators believed that the disease was inherited,'.' and pedigree analysis indicated that the condition indeed was familial.'~"More recently, investigators recognized that the primary lesions affected glomeruli, and that renal cortical hypoplasia probably was not the cause. Consequently, familial nephropathy (FN) has become the preferred name for the disease?Morphometric studies of kidney specimens from dogs with FN subsequently provided persuasive evidence that the disease was a primary glomerulopathy and not renal hypoplasia."Although FN in Cocker Spaniels was the first hereditary renal disease of dogs to be characterized, its pathogenesis remains unknown. The ultrastructural lesions in Cocker Spaniels with FN have been reported to be similar to those observed in human beings with Alport ~y n d r o m e ,~, '~' but transmission electron microscopic (TEM) findings have been described from only 2 young affected Cocker spaniel^.^,"The purpose of the present report is to describe the clinical and pathologic findings in 4 juvenile English Cocker Spaniels with advanced renal failure due t o suspected FN.
Materials and MethodsThe subjects of this report are 4 English Cocker Spaniels that were referred to the Texas Veterinary Medical Center (TVMC) for evaluation of renal disease between 1992 and 1995. After clinical evaluation, the affected dogs were euthanized and necropsied. For comparative purposes, a renal biopsy specimen was obtained from a young English Cocker Spaniel with normal renal function at the time of routine ovariohysterectoniy.Clinical evaluations were performed by conventional methods. Histories were reviewed, and coniplete physical examinations were performed. CBCs, serum biochemistry, and urinalyses were performed in our hospital using standard methods. For urine protein-creatinine ratios, urine protein concentrations were determined by a turbidimetric method (DuPont Discrete Clinical Analyzer, Medical Products Division, ...
