Hereditary nephritis. Early clinical, functional, and morphological studies.

Extract: The accumulation of literature on hereditary nephritis with or without deafness attests to the increased awareness of the existence of this syndrone. It is the purpose of his report to show that there are distinguishing histologic findings in young paitents with minimal disease and normal renal function. Eleven paitents were studies; 4 were females and 7 were males. Releveant family histories and clinical laboratory findings are shown in table I. In all paitents, hematuria, gross or microscopic, was present. Exacerbations of the hematuria occurred as a part of the exaggerated response of these paitents to upper respiratory infection. Renal functional data are shown in table II. These data were generally within normal limits for our laboratory. Table III outlines the morphologic findings observed on renal biopsy. In renal biopsies obtained from 10 patients, there was observed persitence of fetal-like glomeruli characterized by the circumferential crowding of visceral epithelium and an apparent decrease in the number of patent capillaries. The most striking finding in the tubules was the presence of red cell and blood cell casts seen mainly in the distal and collecting tubules. Foam cells were an infrequent finding but, when presnt, were unassociated with interstitial fibrosis. Examination of kidney specimens under the electron microscope reveated the presence of at least ferential crowing of visceral epithelial cells, particularly at the surface, facing Bowman's capsule. These epithelial cells were characterized by large nuclei, small amounts of cytoplasm, apparently poorly developed introacytoplasmic organelles, and fiequent villous-like cytoplasmic projections on the surface. In families from whom past histories are unavailable, recognition of distinct renal biopsy characteristics would help identify this syndrome in the early stages of disease. At this stage, the combination of morphologic features considered to be characteristic would include the presence of a) fetal-like glomeruli, which were seen by electorn microcscopy in 7 paitents and by light microscopy in 10 patients; blood cell casts; and d) foam cells in the absence of interstitial fibrosis. The fetal-like glomeruli present in our paitents did not correspond to any of the normal stages of glomerular development observed under electron microscopy by other investiagators, but rather, appeared to represent dysgenesis. Most patients from whom data are reported were more than 2 years of age, at which time fetal gomeruli are exceptional. Of interest was the observaton that almost identical histology was found to exist among the siblings. Speculation: The fetal-like glomeruli observed on renal biopsy might be the result of either a developmental abnormality or dysgensis. The changes obeserved in all glomeruli studied by electron microscopy suggest that even those glomeruli that appear to be morphologically unchanged under light microscopy were involved in or by the pathologic process. It is suggestd that there is a common rather than a divers etiology for ranal disease in children. Longgitudinal follow-up with repeated renal functionl studies and biopsies will be needed to delineate the natural history.