Renal abnormalities in the Bardet-Biedl syndrome

Four cases of BARDET-Biedl syndrome (BBS) are described which all suffer from renal abnormalities. Polyuria or polydipsia with impairment of renal concentration capacity were the earliest signs of renal dysfunction. Renal insufficiency developed in 3 cases and hypertension in two. Urographic abnormalities were demonstrated in all patients. The most remarkable features were cystic spaces communicating with the calices and lobulation of kidney. Caliceal clubbing and caliectasis surrounded by narrowed, unscarred parenchyma were frequent findings. Previous investigators reported various renal histological pictures in BBS. We found tubulo- interstitial lesions in all cases. Features of dysplasia and cystic formations were less frequent. Mesangial proliferation was not noted. Ultra-structural changes in the glomerular basement membrane were not observed in this study. Thirty-one of 32 recently reported cases of BBS included renal lesions which are the major cause of death. It is therefore suggested that renal abnormalities are accepted as the cardinal feature of this syndrome.

Alport's syndrome: experience at Hôpital Necker

We review the characteristic morphologic features identifiable by electron microscopy that have been described in patients presenting with Alport's syndrome. They are diffuse thickening and splitting of the glomerular basement membrane (GBM), which are either isolated or associated with thinning. In occasional cases, only diffuse thinning can be seen. Our study of 100 families followed in Necker's hospital, of which 60 patients have had electron microscopic examination of their renal parenchyma, demonstrates that these GBM changes are highly suggestive of Alport's syndrome. All the patients included in the study fulfilled the following clinical criteria: familial incidence, nerve deafness in the propositus or in another member of the family, renal disease with progression to renal failure in the proband or in another member of the kindred. Although a failure in the proband or in another member of the kindred. Although a normal GBM was found in five patients, the GBM changes should be one of the criteria for the definition of the syndrome. Results dealing with a few other problems raised by this syndrome are reported. They concern the antigenicity and the biochemical composition of the GBM, the incidence of macular and perimacular changes, and the genetic transmission of the disease. It is concluded that Alport's syndrome is genetically heterogeneous and that the GBM ultrastructural changes are observed in most patients whatever the type of genetic transmission.

A new form of familial glomerulonephritis

An unusual familial glomerular disease, characterized by the presence of diffuse round mesangial deposits of C3, is described in 2 siblings (1 male and 1 female) and their mother. The clinical picture in the 3 patients was a long-lasting proteinuria. An acute hemolytic uremic syndrome with malignant hypertension developed in the male at the age of 24 years, requiring bilateral nephrectomy. The glomerulonephritis recurred on a renal allograft. This disease is not HLA-linked and no characteristic abnormality of complement profile was seen in the 3 patients.

[Prognosis of nephrosis]

Renal biopsy, the introduction of immunohistologic methods and electron microscopy have allowed the differentiation of clinicopathologic entities associated to nephrotic syndrome. Two main categories must be differentiated: in the first, diffuse lesions of the glomerulus, including those secondary to specific diseases the same as those that are apparently primary, are responsible for the increased permeability of glomerular capillaries. Any one of the following clinical signs suggests this category: acute onset with nephritic syndrome, moderate nephritic syndrome, moderate nephrotic syndrome, gross hematuria, persistent hypertension and/or renal failure, poor selectivity of proteinuria and drop in complement serum levels (C3). In the second category, known as idiopathic nephrotic syndrome, the mechanism of disorder of the glomerular capillary is unknown and the nephrotic syndrome is more marked. In most cases with idiopathic nephrotic syndrome, minimal glomerular lesions (MGL) are present. The clinicopathologic correlation among these three types of lesions shows that the type with MGL is characterized by selective proteinuria, absence of hematuria, good response to corticosteroids and good outlook; whereas in types with diffuse mesangial proliferation (DMP) and segmentary sclerosis, proteinuria is frequently non selective, hematuria shows in 50 to 75% of the patients; prognosis is poor. However, MGL, DMP and focal segmentary glomerular sclerosis are not different entities, but represent variants of the same disease. Considering that corticosensitive nephrosis to this moment is the most common cause of the nephrotic syndrome, especially in children under 8 years, renal biopsy should be done only under two circumstances: a) when the clinical symptoms suggest diffuse glomerular lesions and b), when resistance to corticosteroids becomes evident.

Nephrotic syndrome associated with T-cell lymphoma

Glomerulopathies associated with non-Hodgkin's malignant lymphomas have been observed rarely. Previous reports have never determined the cell type of the lymphoproliferative disorder. This report documents a case of nephrotic syndrome in a patient with T-cell derived non-Hodgkin's lymphoma. The neoplastic cell was studied in terms of cell-surface markers, cytochemical staining, and ultrastructural morphology. Nephrotic syndrome occurred shortly after the apparent onset of the lymphoma. The kidney biopsy specimen was examined by light, fluorescence, and electron microscopy. Histologic findings were consistent with the diagnosis of mild focal and segmental glomerulosclerosis. Such an association, reported here for the first time, may support the hypothesis of a pathogenetic link between acquired T-cell abnormalities and glomerular diseases with minimal histologic injury.

Prolonged renal survival and stunting, with protein-deficient diets in experimental uremia. Reversal of these effects by addition of essential amino acids

The aim of dietary therapy of chronic renal failure is to reduce uremic symptoms while avoiding malnutrition. The possible toxic effects of the diet on the kidney are rarely taken into consideration. The present experiment compared the long-term effects of three low-protein diets in nephrectomized rats (UI, UII, UIII) and in controls: diet I containing 7.5% protein, diet II containing 7.5% protein + 1% EEAs, and diet III containing 14% protein. Nephrectomized rats gained less weight than corresponding controls. UI rats had a decrease in the rate of length gain as opposed to groups UII and UIII. UI, however, maintained a relatively constant GFR, whereas groups UII and UIII had severe reductions in renal function. There were no significant differences between either UII or UIII rats in terms of growth and survival, despite lower consumption not only of proteins but also of all nutrients in the former group measured in a previous study. Thus semisynthetic diet appeared of little benefit. A diet consistent with both normal growth and preservation of renal function remains to be defined.

Glomerular basement membrane changes in nonhereditary glomerular diseases

Some examples of glomerular lesions developing in different types of nonhereditary glomerular diseases have been described. In most of them, secondary glomerular basement membrane changes are important factors in the development and progression of the glomerular lesions. When severe, they initiate irreversible glomerular scar formation.

Glomerular basement membrane changes in hereditary glomerular diseases

Ultrastructural glomerular basement membrane changes are present in most hereditary glomerular diseases: thick and thin basement membrane with splitting of the lamina densa in Alport's syndrome, thin basement membrane in familial benign essential hematuria, and thick basement membrane with the presence of collagen-like fibrils in the nail-patella syndrome. They are useful markers for diagnosis. Moreover, their knowledge has set the problem of the primary biochemical defect in basement membrane metabolism accounting for morphological abnormalities and clinical disturbances. Further biochemical and immunochemical investigations are still required for a better understanding of hereditary glomerular diseases.

[Arterial hypertension caused by anomaly of the renal artery or its branches in children]

38 cases of severe hypertension due to a vascular abnormality of the renal pedicle were studied in children under 16 years of age, 18 boys and 20 girls. The most common presentation was at routine clinical examination. The diagnosis of an abnormality of the renal artery was suggested by the appearances of intravenous urography. There were many causes; 4 aneurysms of the renal artery or its branches, 4 fibromuscular dysplasias with one case of bilateral fibromuscular dysplasia, 4 idiopathic stenoses, 2 endarteritis, and 6 thromboses revascularised to variable degrees (2 after umbilical vein catheterisation and one due to DLE). In three cases the hypertension was related to compression of the pedicle by a tumour of haematome, and 14 cases had multiple arterial lesion. In the latter group, 6 cases of neurofibromatosis, 2 cases of William and Beuren's disease, 1 case of generalised Elastorhexia, 2 cases of aortic medio stenosis, probably Takayashu's disease, and 3 unidentified conditions. Surgery was performed on 29 patients, 21 of whom had unilateral lesions and were definitively cured of hypertension. Of the 8 cases with multiple lesions, only 2 were completely corrected with cure of their hypertension.

Effect of various protein diets on growth, renal function, and survival of uremic rats

The effects on growth, renal function, and survival of three isocaloric diets of various protein content (14, 27, and 37 g/100 g in diets I, II, and III, respectively) were compared in uremic rats and in controls. Diet I provided the minimal requirements in all amino acids for gorwing rats. In controls fed ad lib, weight and length gain were better with high protein diets, whereas they were inversely related to the diet protein content in uremic rats. The higher the protein intake, the higher the progressive elevation of BUN and serum creatinine and the mortality rate. Because proteins were supplied by fish flour, their increase was associated with increased mineral content, and the conclusions are restricted to the use of natural proteins: a moderately restricted protein diet securing only the minimal requirements had a beneficial effect on growth and survival of rats with reduced kidney mass. Avoiding any excess in proteins from the early stage of renal disease is suggested.

The significance of pure diffuse mesangial proliferation in idiopathic nephrotic syndrome

The prognostic significance of the finding of diffuse mesangial proliferation (DMP) in patients presenting with idiopathic nephrotic syndrome (INS) has not been well established. The clinical course, therapeutic response and final outcome of 38 patients in whom renal biopsy showed DMP are reported. They have been subdivided into 2 groups according to the absence (18 patients: group I) or presence (20 patients: group II) of superimposed lesions of focal and segmental sclerosis and/or hyalinosis (FSS/H). Clinical presentation was similar in both groups although patients in group I were less severely affected. Non of the patients of group II responded to corticosteroids, whereas in group I 2/16 responded and 2 infants remitted without treatment. At the latest assessment, 5/18 patients in group I and 10/20 in group II had progressed to terminal renal failure or had impaired renal function. Five patients in group I and 3 in group II were in clinical remission. Eight of 11 repeat biopsies performed in patients of group I showed the development of FSS/H. Thus patients with DMP seem prone to develop lesions of FSS/H. Their course if often worse than that of minimal change with FSS/H since 7 of the 10 patients who developed renal failure did so within 3 years of onset. The finding of DMP in a patient with idiopathic nephrotic syndrome is usually but not invariably an ominous feature.

[Prolonged glomerulonephritis and cyanotic heart disease]

Three children with congenital heart disease presented with more or less severe renal dysfunction. Histologic studies showed signs of membranoproliferative pseudoglomerulonephritis without deposits on immunofluorescence. Surgical correction of the heart defect induced a spectacular functional and histologic improvement.

[Fabry's disease. Carbamazepine therapy in acrodyniform syndrome]

A 19 year old male affected with Fabry's disease suffered from severe nervous manifestations. Despite very peculiar pains of the extremities, the diagnosis has been missed for a long time and was painted out at this age because of sharp reconstitution of the family history. Fabry's disease was confirmed by discovering typical corneal lesion, a low leucocyte (W.B.C.) alpha-galactosidase activity and foam cells in renal glomerular epithelium. The importance of an early diagnosis is obvious in this case: 10 Instead of degrading narcotic therapy, Carbamazepin brought forward normal social and school living. 20 Familial investigations show up that all the siblings were affected (three boys including the propositus)--several symptoms were found in the heterozygous conductor mother. Despite the rarety of Fabry's disease, the authors emphasize the easiness of diagnosis on simple clinical and biochemical grounds. The authors insist on the symptomatic and therapeutic action of Carbamazepin or Diphenytoin in order to prevent painfull symptoms which often appear during initial course of the disease.

Dense deposit disease: long term follow-up of three cases of recurrence after transplantation

The incidence and early recurrence after transplantation prove the specificity of the appearance of an electron dense alteration of kidney basement membrane often called dense intra-membranous deposit disease. Three new cases with dense deposit disease affecting the original kidneys have been followed-up after transplantation for periods ranging from 4 to 8 years and illustrate the natural history of the recurrence. Serial kidney biopsies showed the predominance of dense deposits near the mesangial area and the vascular pole. These deposits were also seen in some tubular basement membranes. Absence of cell proliferation was noted in all biopsies performed. Immunofluorescence studies revealed fixation of C3 alone. Histological signs of recurrence are compatible with the absence of clinical and biological signs. Transient or permanent proteinuria and microhematuria were common findings. Serum complement levels, measured after transplantation, were low in all three cases. Despite recurrence of the original glomerulonephritis, long-term survival of the graft was commonly observed, two cases being followed-up for 7 and 8 years. Patients with dense intra-membranous deposits glomerulonephritis should not be excluded from a transplantation program. One of the three cases reported here illustrates the exceptional association of recurrence of dense intramembranous deposits, de novo membranous glomerulonephritis and chronic rejection.