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RENAL PATHOLOGY OF FETUSES WITH CONGENITAL NEPHROTIC SYNDROME OF THE FINNISH TYPE
Author(s) -
AUTIOHARMAINEN HELENA
Publication year - 1981
Publication title -
acta pathologica microbiologica scandinavica section a pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.909
H-Index - 88
eISSN - 1600-0463
pISSN - 0365-4184
DOI - 10.1111/j.1699-0463.1981.tb00212.x
Subject(s) - lamina densa , basement membrane , cytoplasm , glomerular basement membrane , pathology , reabsorption , mesangial cell , chemistry , vacuole , lamina lucida , biology , glomerulonephritis , basal lamina , microbiology and biotechnology , kidney , ultrastructure , endocrinology , medicine
A qualitative and quantitative transmission electron microscopic study was performed on kidneys of fetuses with congenital nephrotic syndrome of the Finnish type (CNF) and controls obtained from elective pregnancy terminations. The gestational age of the fetuses ranged from 16–22 weeks. A consistent qualitative change of CNF glomeruli was the nearly total loss of epithelial cell foot processes, with smudging of epithelial cytoplasm as broad masses on the glomerular basement membrane. Adjacent to the basement membrane there were increased amounts of fibrillar material in the epithelial cytoplasm. The number of pinocytic droplets was increased both in epithelial and endothelial cytoplasm and some of the capillary loops showed swelling of endothelial cells with poor fenestrations in cases of CNF. Mesangial hyperplasia was focally evident in the most mature CNF glomeruli with an increase of the mesangial matrix. A striking qualitative feature in CNF, only rarely seen in controls, was the occurrence of electron lucent vacuoles and heteromorphic residual bodies in the mesangial cell cytoplasm. The total thickness of the glomerular basement membrane was comparable in CNF and controls but the width of the lamina densa was significantly smaller in CNF than controls. Lamina rara interna of the basement membrane showed irregular widening with accumulation of coarse granular material. Reabsorption droplets of proximal tubular cytoplasm were significantly increased in CNF. With the dilatation of the tubule the droplets almost totally disappeared. Based on the results of the study it is suggested that the basic pathogenetic defect in CNF lies in faulty development of the lamina densa of the glomerular basement membrane and, secondary to this, various glomerular and tubular changes occur. In addition to evidence of extensive foot process fusion, mesangial cell cytoplasmic vacuoles represent a diagnostically important qualitative change in the glomeruli of fetal CNF.