Congenital nephrotic syndrome, diffuse mesangial sclerosis, and bilateral cataract

A case of congenital nephrotic syndrome with diffuse mesangial sclerosis and bilateral cataract without other ocular anomalies is presented. This association, to our knowledge, has not been reported before.

Haplotype analysis of congenital nephrotic syndrome of the Finnish type in non-Finnish families

Congenital nephrotic syndrome of the Finnish type (CNF) has an estimated incidence of 1 in 8000 newborns in the genetically isolated population of Finland. Although the disease is most common in Finland, it occurs throughout the world in families without known Finnish origin. In the past, these authors recently localized the CNF gene to the chromosome 19q13.1 region and observed strong linkage disequilibrium to the genetic markers D19S610, D19S608, D19S224, and D19S220 in Finnish families. In these Finnish families, four main CNF haplotype categories have been observed. In the study presented here, haplotype analysis was applied to several non-Finnish CNF families to determine whether the same genetic locus is involved in these families. The results of the haplotype analysis suggest linkage to the 19q13.1 chromosomal region. It was also observed that, in most cases, alleles typically found on CNF chromosomes of Finnish families are also found on CNF chromosomes of non-Finnish families from North America and Europe. In these families, the strongest association was found with marker D19S608. These findings suggest that Finnish and many non-Finnish CNF cases share the same disease locus.

Noncollagenous matrix components of glomeruli in congenital nephrotic syndrome of the Finnish type: evidence of abnormal splitting of nidogen?

The congenital nephrotic syndrome of the Finnish type (CNF) is a rare autosomal recessive disease with proteinuria starting already in utero, prematurity and nephrotic syndrome developing within the first weeks of life. The basic defect of this disease is unknown but has been suggested to be restricted to the kidney glomeruli and especially to the glomerular basement membrane (GBM). The location of the major matrix components in the glomeruli of CNF patient kidneys has previously been reported. Using indirect immunofluorescence microscopy we here describe the more recently characterized components of the glomerular extracellular matrix, including nidogen, tenascin, vitronectin and chondroitin sulfate proteoglycan in CNF and control kidney glomeruli. The accumulation of tenascin and chondroitin sulfate in the renal interstitium as well as a more granular deposition pattern of vitronectin in the mesangium of CNF glomeruli as compared to the control kidneys were observed. These changes were considered secondary to the massive proteinuria, reflected also by the presence of glomerular sclerosis and interstitial fibrosis in the CNF kidney samples. Additionally, analysis of GBM components by immunoblotting revealed either increased or decreased proportionate amounts of fibronectin and laminin in the GBM of CNF kidneys, respectively. Interestingly, different proportionate amounts of proteolytic fragments of nidogen were found in CNF glomeruli as compared to controls. Equal levels of nidogen mRNA were found in the cortical tissue of CNF and control glomeruli. Since nidogen is crucial for the supramolecular organization of basement membranes, these results suggest that an unusual fragmentation of nidogen, due to abnormal assembly, degradation or reorganization of glomerular extracellular matrix, may be associated with the basic defect of CNF.

Distribution of renal integrin receptors and their ligands in congenital nephrotic syndrome of the Finnish type

The aim of this study was to examine the distribution of beta 1 and alpha v integrins (Ints) and some of their ligands in the kidneys of patients with congenital nephrotic syndrome of the Finnish type (CNF) and in controls using indirect immunofluorescence with monoclonal antibodies. The mesangial reactivity of Int alpha 1 and Int beta 1 subunits was more variable and an increased glomerular reactivity with Int alpha 3 and Int-alpha 6 antibodies was found in CNF kidneys than in controls. Int alpha 2 subunit was either completely missing from or found in significantly lesser amounts in CNF kidney glomeruli. The immunoreactivity for Int alpha v was more variable, fainter and also more granular in CNF samples than in control kidneys. The glomerular reactivity for Int beta 5 was more diffuse and weaker, and in sclerotic Bowman's capsules more intense in CNF kidneys than in controls. Immunoreactivity for Int beta 6 was restricted and was comparable in extent in CNF and control kidneys. Of the extracellular matrix components studied, the expression of EDAFn, EDBFn, OncFn, Ln alpha 2 chain, Ln beta 1 chain and tenascin was increased. This is also seen in several glomerular diseases with inflammation and sclerosis. Immunoreactivity for vitronectin was decreased. Several differences were found in the intensity or location of the immunostaining for the beta 1 and alpha v Ints and their ligands in CNF kidneys compared with controls, which have not been found in any other proteinuric disease. Disturbed Int expression pattern in CNF may specifically reflect the disturbance of glomerular function caused by the primary defect in this disease.

Endometrial and fetoplacental markers in pregnancies with fetal congenital nephrosis

OBJECTIVE

Congenital nephrotic syndrome of the Finnish type [CNF] is an autosomal recessive disorder leading to death in early childhood, if treated conservatively without early renal transplantation. Prenatal screening at midtrimester is feasible by measuring maternal serum alpha-fetoprotein [MSAFP], elevated amniotic fluid [AF] AFP being the only diagnostic test in population screening. We studied whether concentrations of other pregnancy-related markers offer any ancillary procedure for screening.

METHODS

In a prospective case-control study, the concentrations of maternal serum human chorionic gonadotropin [hCG], unconjugated estriol [uE3], human placental lactogen [hPL] and placental protein 14 [pp14] were measured in samples from six singleton pregnancies associated with fetal CNF and from 18 matched controls at 15 weeks of gestation.

RESULTS

In the CNF group, mean hCG and pp 14 concentrations were slightly elevated, whereas uE3 and hPL concentrations were within the lower normal range. None of these differences were statistically significant and the distribution of these values was too wide to use them for screening.

CONCLUSIONS

Low unconjugated E3 and elevated hCG concentrations were expected, since newborns with CNF are growth-retarded and have large placentas. The extent of these alterations was not sufficient to identify high risk pregnancies. Substantial differences in the maternal serum concentrations of hPL and pp 14 were not observed. Hence, MSAFP screening at midtrimester is the strategy of choice for prenatal detection of CNF.

Congenital nephrotic syndrome of the Finnish type: linkage to the locus in a non-Finnish population

Congenital nephrotic syndrome of the Finnish type (CNF) is inherited as an autosomal recessive trait. The biochemical basis of the disease is unknown, although a lesion in the glomerular basement membrane is strongly suggested. Recently, the CNF locus was assigned to chromosome 19q12-q13.1 on the basis of linkage analysis in Finnish families. The high incidence of the disease in Finland, as well as the demonstration of linkage disequilibrium in the Finnish study, strongly suggests a founder effect based on a common ancient mutation in this population. We confirm linkage of the CNF locus to the same chromosomal region in seven non-Finnish CNF families without evidence of linkage disequilibrium. Our results show that the same gene seems to be affected in both Finnish and non-Finnish CNF populations. However, in the latter the mutation-carrying chromosomes descend from different ancestors without evidence of a founder effect.

Prenatal screening for congenital nephrosis in east Finland: results and impact on the birth prevalence of the disease

Congenital nephrosis of the Finnish type (CNF) is inherited as an autosomal recessive trait which maps to the long arm of chromosome 19. The disease causes massive proteinuria, and renal transplantation in early neonatal life is the only effective treatment. Prenatal diagnosis, usually in high-risk families, depends on the analysis of alpha-fetoprotein (AFP) levels in maternal serum (MS) or amniotic fluid (AF). We studied the effectiveness of MSAFP measurement as a method of screening all pregnant women for congenital nephrosis. Between 1 January 1979 and 31 December 1992, all pregnant women (N = 110,858) attending maternity care units in East Finland were offered serum AFP measurement as part of a screening programme. All patients whose MSAFP value was > or = 2.5 multiples of the median (MOM) at 15-18 weeks' gestation were given an ultrasound examination and if no morphological abnormality was found, they were then offered amniocentesis. Altogether, 105,880 pregnant women (96 per cent) in East Finland participated in the screening for CNF. A total of 47 cases of CNF were diagnosed during the study period. Elevated AFP concentrations in maternal serum and amniotic fluid (> or = 2.5 MOM) were found in all screened (44/105,880) affected pregnancies except one. The most typical feature of a CNF pregnancy was a very high AFP concentration in the amniotic fluid. As a result of the screening, the prevalence at birth of CNF decreased from 1:2600 to 1:11,086. The possibility of CNF has to be taken into account in pregnancies with a ¿false-positive' elevated AFP result (normal ultrasound and no detectable acetyl cholinesterase).

Prenatal diagnosis of diffuse mesangial glomerulosclerosis by ultrasonography: a longitudinal study of a case in an affected family

The 4th child of an Arabian consanguineous family with 2 previous infant deaths due to diffuse mesangial glomerulosclerosis (at the ages of 1 and 44 days) and 1 healthy 3-year old child was followed up by ultrasonography from the 9th until the 35th week of gestation. Ultrasound showed enlarged hyperechogenic kidneys from the 14th week onwards, and the amniotic fluid level was increased to the upper normal limit. An amniocentesis at 14+ weeks of gestation showed a normal male karyotype and normal alpha-fetoprotein levels in amniotic fluid and maternal serum. Albumin and alpha 1-microglobulin levels in the amniotic fluid were within the normal range and not useful for diagnostic purposes. The child was born at the 36th week of gestation and died of renal failure 21 days later. A postmortem renal biopsy specimen revealed diffuse mesangial glomerulosclerosis.

Diffuse mesangial sclerosis: a unique type of congenital and infantile nephrotic syndrome

Clinical and pathological findings in four Turkish infants with isolated diffuse mesangial sclerosis (DMS) are presented. All the patients were offsprings of consanguineous marriages and two had similarly affected sibs indicating an autosomal recessive inheritance. The onset of the nephrotic syndrome was at 7, 17, 11 and 3 months of age. They all died in a state of renal failure complicated by infections at the ages of 11, 33, 13 and 5 months. DMS was diagnosed at postmortem examination in all. Fluorescence-microscopical studies in all and an electron-microscopical study in one revealed nonspecific findings. The shorter survival in three of the cases was thought to be due to intervening infections. The variation of the clinical features along with the fluorescence and electron-microscopical findings are consistent with the previously mentioned heterogeneous aspect of DMS.

Congenital nephrotic syndrome: a novel phenotype of type I carbohydrate-deficient glycoprotein syndrome

Type I carbohydrate-deficient glycoprotein (CDG) syndrome is a genetic multisystem disorder generally without overt renal problems. We report a neonate with neurological abnormalities and congenital nephrotic syndrome of diffuse mesangial sclerosis type. Serum transferrin isoelectric focusing showed the typical abnormalities of type I CDG syndrome. Normal transferrin focusing findings in other patients with similar renal problems excluded the possibility of a secondary biochemical phenomenon. The diagnosis of type I CDG syndrome was confirmed by demonstration of a deficiency of phosphomannomutase. No evidence of pontocerebellar atrophy was found in imaging or at autopsy. We conclude that congenital nephrotic syndrome may occur in type I CDG syndrome, and that this diagnosis should be considered in patients with congenital nephrotic syndrome. Absence of pontocerebellar atrophy does not exclude the diagnosis of type I CDG syndrome.

Congenital nephrotic syndrome

Congenital nephrotic syndrome (CNS) can be caused by neonatal infections, renal diseases which exceptionally occur in early infancy and syndromes with a renal histology of DMS. The most common CNS is the Finnish-type (CNF), an autosomal recessively inherited disease characterized by intrauterine onset of massive proteinuria. The CNF gene has been localized to the long arm of chromosome 19, but the pathogenesis remains unclear. Forty-six CNF patients have been treated at our institution. The diagnosis was based on family history, severe proteinuria of intrauterine onset (serum albumin < 10 g/liter at presentation and urinary protein > 20 g/liter when serum albumin was corrected to > 15 g/liter), a large placenta (> 25% of birth wt), exclusion of other CNS-types and normal glomerular filtration rate during the first six months. Treatment included i.v. albumin substitution, optimal nutrition, thyroxine and anticoagulation. Forty-one patients had been nephrectomized bilaterally at a mean age of 1.2 years and after 3 to 25 months on peritoneal dialysis renal transplantation (Tx) had been performed on 34 who were a mean age of 2.2 years. Growth and development has been normal. Patient survival after Tx was 97%, graft survival 94%, 81% and 81% one, three and five years after Tx was (50% cadaver grafts). Mean GFR was 75 ml/min/1.73 m2 after three years, mean height SDS -1.42, and the nine oldest patients attend school in a normal class.

Fine mapping and haplotype analysis of the locus for congenital nephrotic syndrome on chromosome 19q13.1

We have recently localized the gene for congenital nephrotic syndrome of the Finnish type (CNF) to chromosome 19q12-13.1. On the basis of observed recombination events, the gene was localized between markers D19S416/D19S425/D19S213/D19S208/D19S191 and D19S224. Here we have extended the mapping efforts, on the basis of a detailed physical map of the region. By means of three new polymorphic markers--D19S608, D19S609, and D19S610--developed in this study, the critical candidate region could be further restricted. Significant linkage disequilibrium was observed with markers D19S610, D19S608, D19S224, and D19S220, the strongest allelic association being 84% with marker D19S610 at 19q13.1. This suggests that the CNF gene locus lies in close proximity to marker D19S610. Combination of the informative markers revealed four main haplotype categories. Different geographic distribution was observed between these haplotype groups when they were placed on the map of finland according to the birthplaces of grandparents.

Mesenteric arterial thrombosis complicating congenital nephrotic syndrome of Finnish type: report of one case

A female, term neonate presented with generalized edema, heavy proteinuria, hypoalbuminemia and hyperlipidemia in the second week of life. The clinical and laboratory features were compatible with the diagnosis of congenital nephrotic syndrome. Treatment included albumin infusion, empirical penicillin, steroid and continuous arterio-venous hemofiltration. Intestinal perforation developed at the 19th day of age and led to a fatal outcome. At autopsy, thrombosis of the superior mesenteric artery and its branches was noted, and histology of the kidney was compatible with congenital nephrotic syndrome of the Finnish type. The risk of thromboembolism, arterial or venous, should be considered in patients with nephrotic syndrome, even in the neonatal period. Preventive measures, including avoiding volume depletion and femoral arterial/venous puncture, are essential in managing these patients. Prophylactic anticoagulation and infusion of fresh frozen plasma may be warranted to avoid such potentially lethal complications of thromboembolism.

Glomerular anionic charge in congenital nephrotic syndrome of the Finnish type

Decrease of the anionic charge of the glomerular basement membrane and especially the reduced amount of heparan sulphate proteoglycan in the lamina rara externa has been suggested to be the basic pathogenetic defect in congenital nephrotic syndrome. In the present study the anionic charge of glomeruli was examined in the congenital nephrotic syndrome of the Finnish type and in controls using cationic stains (polyethyleneimine, Ruthenium Red) in electron microscopy. Chondroitinase and heparinase treatments were used to characterize further the anionic elements detected. Scanning electron microscopy (SEM) was used in addition to transmission electron microscopy (TEM) to examine the tridimensional structure and secondary changes of podocytes in this syndrome. The number (mean +/- SD) of polyethyleneimine granules per 1 micron length of lamina rara externa of the glomerular basement membrane was 24.9 +/- 4.5 in control and 23.2 +/- 4.3 [corrected] in congenital nephrotic syndrome subjects. The Ruthenium Red staining pattern was closely similar in syndrome and control kidneys. The granules evident after staining with either cationic stain were seen after chondroitinase but not after heparinase treatment in control as well as in syndrome patient kidney samples. No denuded areas of basement membrane in 42 glomeruli from four syndrome patients were found in SEM. In conclusion, the amount of anionic sites in the lamina rara externa as detected by either cationic stain was comparable to controls. These results do not support the hypothesis of decreased anionic sites in the lamina rara externa of the glomerular basement membrane in congenital nephrotic syndrome of the Finnish type.

Amniotic alpha-fetoprotein in the prenatal diagnosis of congenital nephrotic syndrome of the Finnish type

Congenital nephrosis of the Finnish type (CNF) is rare outside Finland, where the incidence may be as high as 1 in 2000 live births. Neonates with the disorder develop renal failure within the first months of life and without renal transplantation, the prognosis is extremely poor. This case report describes a woman's three pregnancies, two of which were affected with CNF.

Localization of extracellular matrix components in congenital nephrotic syndromes

While renal tissue from one fetus and a newborn with congenital nephrotic syndrome, Finnish type (FCNS), showed a normal basement membrane (BM) localization and composition, in another type of congenital nephrotic syndrome, diffuse mesangial sclerosis (DMS), most glomeruli demonstrated a completely disorganized matrix. In the latter, hyalinized glomerular segments were composed of irregular deposits of interstitial collagens I, III, V, and extensive deposits of heparin sulphate proteoglycan (HSPG), while collagen IV and laminin were completely absent in those areas. Apart from these sclerosed glomerular areas, normal capillarly loops revealed a matrix composition that was comparable to normal glomeruli. The additional immunolocalization of various extracellular matrix components during the development of normal human glomeruli revealed some significant age-dependent changes both in the localization of interstitial collagens and BM components: interstitial collagens I and III disappeared after the first S-shaped indentations appeared, while the interstitial collagen V remained along the glomerular BM and within the mesangium. The BM components showed no significant qualitative changes, but quantitative changes, with a post-natal relative decrease in the collagen IV and laminin content when compared with the level of BM-associated HSPG. Our results provide circumstantial evidence that the composition of the extracellular matrix (and in particular of the BM) shows age-dependent quantitative changes which may be associated with functional adaptation processes of the developing kidney. The observed matrix composition in the two different congenital nephrotic syndromes suggests various pathomechanisms which may be located either in the molecular structure of the negatively charged molecules (e.g. abnormal sulphatation of HSPG in FCNS) or in the dysregulated synthesis of various matrix components (DMS).

Congenital nephrotic syndrome

A six week old baby girl from a closed Malay community in Hambantota presented with gradually increasing oedema since two weeks of age. She was oedematous, with gross non selective proteinuria, hypoproteinaemia and hypercholesterolaemaia. Congenital nephrotic syndrome is extremely rare and has not been reported previously in Sri Lanka.

Characteristic phenotype in congenital nephrotic syndrome

We present three children with congenital nephrotic syndrome and previously undescribed facial features. These include: (1) small mouth (intercommissural distance < 3rd percentile); (2) tented upper lip; (3) small nose (interalar distance -2 SD below mean); (4) fullness of cheeks giving a 'jowly' appearance; (5) overhanging outer thirds of upper eyelids. These features may reflect prolonged tissue oedema and protein malnutrition in utero and early life. CONCLUSION Characteristic facial features in congenital nephrotic syndrome may reflect intra-uterine malnutrition.

Congenital nephrotic syndrome with clinical hypothyroidism

A 15 month old boy with typical features of congenital nephrotic syndrome (CNS) is reported, who in addition to the renal pathology had an associated clinical hypothyroidism with low levels of total and free thyroxine and triiodothyronine and an elevated serum TSH. Improvement in the physical parameters and mental status from thyroid hormone replacement therapy is documented.

The nephrotic syndrome

In children the nephrotic syndrome is an uncommon condition characterised by heavy proteinuria, hypoalbuminaemia and oedema. It is most commonly associated with minimal glomerular changes and is usually responsive to steroids.

Management of congenital nephrotic syndrome of the Finnish type

Congenital nephrotic syndrome of the Finnish type (CNF) is a rare autosomal recessively inherited disease characterised by intrauterine onset of massive urinary loss of proteins, 90% of which is albumin. The CNF gene has been localised to the long arm of chromosome 19, but the pathogenesis remains unclear. Historically, all CNF patients died, usually within the first 6 months of life. Today, a normal life can be achieved for a child with CNF by correcting the protein deficiency and normalising nutrition. This is accomplished by early intravenous albumin supplementation, nutritional support, aggressive treatment of complications and early renal transplantation, after bilateral nephrectomy and peritoneal dialysis. In the present article current treatment strategies are reviewed, and our own experience with 43 CNF patients during the last 10 years is presented.

Successful treatment of Finnish congenital nephrotic syndrome with captopril and indomethacin

Two infants with biopsy-proven microcystic Finnish congenital nephrotic syndrome (onset at birth) were treated with a combination of captopril and indomethacin for 2 1/2 and 2 years, respectively; they had a marked reduction of urinary protein excretion without further need for albumin infusions. One infant has end-stage renal disease; the other infant's glomerular filtration rate has remained within normal limits.