Hereditary nephritis with a characteristic renal lesion

Negative Staining for COL4A5 Correlates With Worse Prognosis and More Severe Ultrastructural Alterations in Males With Alport Syndrome

Introduction

Alport syndrome (AS) is a genetic disorder characterized by progressive hematuric nephropathy with or without sensorineural hearing loss and ocular lesions. Previous studies on AS included mostly children.

Methods

To determine the prognostic value of loss of staining for collagen type IV alpha 5 (COL4A5) and its relationship with the ultrastructural glomerular basement membrane alterations, we performed direct immunofluorescence using a mixture of fluorescein isothiocyanate-conjugated and Texas-red conjugated antibodies against COL4A5 and COL4A2, respectively, on renal biopsies of 25 males with AS (including 16 who were diagnosed in adulthood).

Results

All patients showed normal positive staining of glomerular basement membranes and tubular basement membranes for COL4A2. Of the 25 patients, 10 (40%) patients showed loss of staining for COL4A5 (including 89% of children and 13% of adults) and the remaining 15 (60%) had intact staining for COL4A5. Compared with patients with intact staining for COL4A5, those with loss of staining had more prominent ultrastructural glomerular basement membrane alterations and were younger at the time of biopsy. By Kaplan-Meier survival analysis and Cox regression analysis, loss of staining for COL4A5 predicted earlier progression to overt proteinuria and stage 2 chronic kidney disease or worse. By multivariate Cox regression analysis, loss of staining for COL4A5 was an independent predictor of the development of overt proteinuria and stage 2 chronic kidney disease or worse.

Discussion

Thus, the COL4A5 expression pattern has an important prognostic value and it correlates with the severity of ultrastructural glomerular basement membrane alterations in males with AS. Loss of COL4A5 staining is uncommon in patients with AS diagnosed in their adulthood.

Histologic and Ultrastructural Studies of Juvenile Onset Renal Disease in Four Rottweiler Dogs

Juvenile onset renal disease is described in 2 male and 2 female young Rottweiler dogs. Histologic changes in all dogs were cystic dilatation of Bowman's space, mesangial hypercellularity, and glomerulosclerosis. Three dogs also had glomerular crescents and moderate to severe interstitial fibrosis. Electron microscopy revealed glomerular basement membranes of variable thickness, with extensive splitting or lamellation of the lamina densa. These ultrastructural findings are similar to those found in people and in other breeds of dogs with inherited defects in type IV collagen.

Hereditary nephritis mimicking immune complex-mediated glomerulonephritis

The defining ultrastructural features of hereditary nephritis are "basket weave" lamellation or thinning of glomerular basement membranes. Electron-dense deposits are not seen and immunofluorescence (IF) is generally negative. In this study, we report 5 cases of hereditary nephritis in which substantial amounts of glomerular electron-dense deposits were identified on electron microscopy, with corresponding positive IF staining in 4 cases, suggesting immune complex-mediated glomerulonephritis. However, no case had histological evidence of glomerular endocapillary or extracapillary proliferation or leukocyte infiltration typical of active glomerulonephritis. Four cases were diagnosed at outside institutions simply as forms of glomerulonephritis without considering the possibility of hereditary nephritis and were sent for consultation in contemplation of possible immunosuppressive therapy. All patients had negative serologies and no known underlying infectious or autoimmune disease; 4 patients had family history of hematuria or renal disease. The glomerular electron-dense deposits were predominantly mesangial (4 cases) and intramembranous (4 cases), as well as subepithelial (2 cases) or subendothelial (1 case). Corresponding IF positivity for immune reactants was identified in 4 cases, and IgG was the predominant immunoglobulin deposited. A characteristic feature was the tendency for deposits to form between the complex layers of glomerular basement membrane material, favoring a process of nonspecific entrapment of immune reactants within the thickened, lamellated basement membrane. In all cases, a diagnosis of hereditary nephritis was confirmed by demonstration of the characteristic loss of immunoreactivity for the alpha5 subunit of collagen IV (4 cases) or Goodpasture's antigen (1 case) in renal or epidermal basement membranes. These cases expand the spectrum of unusual pathological findings in hereditary nephritis and emphasize the potential for hereditary nephritis to mimic immune complex glomerulonephritis.

Alport's syndrome

Images

Nonfamilial hematuria associated with glomerular basement membrane alterations characteristic of hereditary nephritis: comparison with hereditary nephritis

Characteristic ultrastructural alterations of the glomerular basement membrane (GBM) have been reported in hereditary nephritis and in children without a family history of renal disease. The clinical features, renal biopsy findings, and subsequent course were studied retrospectively in 48 children with such GBM changes to compare findings in those with and without a family history of nephritis and to determine the significance of the GBM changes in patients with nonfamilial disease. All 48 patients had hematuria. For 30, there was hematuria in at least one other member of the family (familial hematuria group); for 18, there was no familial incidence. There were no differences between the two groups with regard to clinical and pathologic findings. At the latest follow-up six boys with familial hematuria and three boys with nonfamilial hematuria had reduced renal function, and nine boys with familial hematuria and four boys and one girl with nonfamilial hematuria had neurosensory deafness. Our study results show that children with these GBM changes, with or without a family history of hematuria, tend to have a progressive course, with frequent occurrence of neurosensory deafness, and that the prognosis is more severe in boys. These observations suggest that such GBM changes in patients with nonfamilial hematuria may represent new mutations for hereditary nephritis.

An autosomal recessive disorder with glomerular basement membrane abnormalities similar to those seen in the nail patella syndrome: report of a kindred

We present a 9-year-old boy, the product of a consanguineous marriage, with proteinuria, edema, and microscopic hematuria with mild renal impairment since age 2 yr. Renal biopsy showed the histopathologic electron microscopic changes seen in hereditary osteo-onchyodysplasia (HOOD) [Hoyer et al, 1972; Bennet et al, 1973; DelPozo and Lapp 1970; Vernier et al, 1974; Morita et al, 1973] or "nail-patella syndrome." Neither the patient nor his relatives had bone or nail abnormalities; however, 2 other sibs had died of complications of end-stage renal disease at age 6 and 9, leading us to suspect autosomal recessive inheritance of a severe nephropathy or glomerulodysplasia.

The glomerular basal lamina in hereditary nephritis

Characteristic ultrastructural alterations of the glomerular basal lamina have been reported in hereditary nephritis. The basal lamina is irregularly thickened and the lamina densa shows replication with a "basket weave" pattern, enclosing electron-lucent lacunae which frequently contain small dense particles. However there is controversy regarding the specificity of this lesion in hereditary nephritis. To determine the specificity, 366 renal biopsies from 310 children were studied retrospectively. Twenty-four out of 27 patients with hereditary nephritis showed the characteristic changes of the basal lamina and they were widespread in 17. Two patients with recurrent haematuria but no family history of deafness or haematuria showed similar extensive changes and are regarded as new mutant cases of hereditary nephritis. Similar changes were seen in 17 of the 281 patients with other conditions but were always localized to a few capillary loops. We conclude that a widespread "basket weave" pattern appears to be confined to hereditary nephritis and is seen in the great majority of such cases.

Microscopic hematuria in school children: epidemiology and clinicopathologic evaluation

An unselected population of 8,954 children, age 8 to 15 years, was screened for hematuria. Four urine specimens from each were examined; microscopic hematuria was found in one or more specimens in 4.1%, and in two or more specimens in 1.1% of the children. The prevalence was not age or sex dependent. Those with two or more positive samples were re-examined twice during a half-year period: 33 had hematuria of 6 or more RBC/0.9 mm3, or more than 100,000 RBC/hour, on both occasions; renal biopsy performed on 28 of them revealed two cases of IgA-IgG nephropathy, one of focal segmental sclerosis, one of extracapillary glomerulonephritis, and one of possible hereditary nephritis. In 12 patients the biopsy was entirely normal; the rest showed equivocal changes. Co-existing proteinuria and the degree of hematuria correlated well with the severity of the morphologic alterations. Pathologic findings in microscopic hematuria seem to be less frequent than in hematuria in general; in most such patients, renal biopsy is probably not indicated. In some children the low-grade hematuria may merely represent the upper end of physiologic variation.

Blood coagulation and hereditary nephritis

Nineteen patients with hereditary nephritis - members of six families - were studied for haemostasis on 11 occasions by the use of four capillary tests, 14 different blood coagulation tests and two different platelet function tests. Systemic capillaropathy was demonstrable in 8 out of 15 cases of the non-uraemic, and in all the 5 cases of the uraemic group. No completely normal blood coagulation was found in any of the cases and the coagulation disorders were never of exclusively haemorrhagic pattern. On the evidence of the complex studies, hypercoagulability as well as hyper-hypocoagulability were found in the uraemic and non-uraemic groups alike. Reduction in plasma fibrinolytic activity, elevation of the fibrinogen level and a shift of the thrombelastogram in the direction of thrombosis were demonstrable in the majority of the cases.

Development of the characteristic ultrastructural lesion of hereditary nephritis during the course of the disease

The diagnosis of hereditary nephritis in the absence of a clear family history or the presence of characteristic ancillary abnormalities is difficult, but it has considerable prognostic importance. The recent recognition of an ultrastructural lesion characteristic of this disease, although not present in all families, is of considerable value. In this report we describe a kindred with the lesion-associated disease that differs from those previously described in that the lesion developed during the course of the disease, was not present in all affected members and appeared to be the result of paternal transmission.