Autosomal dominant distal renal tubular acidosis caused by a mutation in the anion exchanger 1 gene in a Japanese family.

Autosomal dominant distal renal tubular acidosis (dRTA) is a rare disorder caused by a mutation in the AE1 gene encoding the chloride-bicarbonate (Cl-/HCO3-) anion exchanger 1 (AE1). Most patients with this disorder present with clinical symptoms in adulthood and their phenotype is milder than that of those with autosomal recessive dRTA. In this report, we describe a Japanese family with autosomal dominant dRTA in which the mother and her daughter presented with severe symptoms caused by hypokalemia at 2 years of age. The heterozygous AE1 mutation G609R, which is a known causative mutation of dRTA, was identified in both patients. To our knowledge, this is the first report of a Japanese family with autosomal dominant type dRTA caused by an AE1 mutation. We, therefore, propose that alterations of AE1 should be considered causative of autosomal dominant dRTA even if typical symptoms appear during early childhood and the clinical features are severe.

Clinicopathologic correlation of C1q nephropathy in children.

BACKGROUND: Clinicopathologic correlation of C1q nephropathy is clarified poorly. The aim of our study is to clarify clinicopathologic correlation in childhood C1q nephropathy. METHODS: Thirty children aged 3 to 15 years who met criteria proposed by Jennette and Hipp were enrolled in this study. RESULTS: According to their presentation at onset, children were divided into 2 groups: the asymptomatic urinary abnormalities (asymptomatic) group (n = 18) and the nephrotic syndrome (NS) group (n = 12). Light microscopy showed minimal change disease (MCD) in 22 children (73%), mesangial proliferative glomerulonephritis in 6 children (20%), and focal segmental glomerulosclerosis (FSGS) in 2 children (7%). Four children in the asymptomatic group and all children in the NS group were administered prednisolone and/or cyclosporine. Normal urinalysis results were found in 8 children in the asymptomatic group and 3 children in the NS group during the follow-up period of 3 to 15 years. Eight children in the NS group were frequent relapsers at the latest follow-up. Two children with FSGS (1 child, asymptomatic group; 1 child, NS group) received dialysis 10 and 15 years after the diagnosis. There were no differences in histological findings and clinical outcomes between the 2 groups. Four children with MCD in the NS group underwent a second biopsy. C1q deposits disappeared in 2 children, and 1 of these 2 children showed FSGS. CONCLUSION: Childhood C1q nephropathy is found in a wide clinical spectrum. Some children showed disappearance of C1q deposits through the follow-up period. A large number of children with C1q nephropathy showed MCD. However, FSGS may develop in some children on repeated biopsy. Therefore, long-term follow-up is needed in children with C1q nephropathy.

Bronchiolitis obliterans organizing pneumonia as an initial manifestation in systemic lupus erythematosus.

Bronchiolitis obliterans organizing pneumonia (BOOP) is a rare complication of adult systemic lupus erythematosus (SLE). This is the first report of a pediatric patient with BOOP as an initial presentation of SLE. She had dyspnea, cough, arthralgia, and erythema on her face. Laboratory examinations revealed pancytopenia, low serum levels of complements, and positivity for anti-nuclear antibody, anti-double stranded DNA antibody, and anti-SM antibody. Her respiratory symptoms, pulmonary function tests, and radiologic findings showed significant improvement after treatment with oral prednisolone. Although it is a rare complication among the pleuro-pulmonary manifestations in SLE, BOOP can be the first presentation, even in pediatric patients.

Clinicopathological correlation of childhood IgA glomerulonephritis presenting diffuse endocapillary proliferation.

The aim of the present study is to clarify the clinicopathological correlation of childhood IgA glomerulonephritis (GN) presenting diffuse endocapillary proliferation. Twenty-seven patients were used in the present study. The 27 patients were divided into three groups (mild, moderate and severe) according to the percentage of glomeruli displaying global endocapillary proliferation per total glomeruli at the first biopsy. The degree of both cellular crescent and lysis of the glomerular basement membrane (GBM) at the first biopsy was semiquantitatively evaluated. The degree of cellular crescent and lysis in the GBM was greater in the severe group than in the mild group. The degree of lysis of the GBM positively correlated with the degree of distribution of endocapillary proliferation. The degree of glomerular sclerosis at the second biopsy was greater in the severe group compared with the other two groups. The severity of cellular crescent at the first biopsy positively correlated with that of glomerular sclerosis at the second biopsy. Multiple logistic regression analysis indicated that the risk of glomerular sclerosis at the second biopsy was 19-fold higher in the odds ratio in the severe group compared with the mild group. In conclusion, the progression of glomerular sclerosis in serial biopsy is dependent on the degree of distribution of endocapillary proliferation and the severity of cellular crescents at the first biopsy in childhood IgA GN presenting diffuse endocapillary proliferation.

Fibronectin glomerulopathy with nephrotic syndrome in a 3-year-old male.

Familial non-immune-mediated glomerulopathy has recently been recognized as a distinct clinical entity. The presentation includes proteinuria, often in the nephrotic range, microscopic hematuria, and hypertension. Renal function may remain intact long term, or may progress slowly to renal failure. A 3-year-old boy was referred with proteinuria (>8 g/day), microscopic hematuria, and hypertension (184/150 mmHg). Renal function was intact. Diagnostic evaluation uncovered no evidence of systemic disease. A renal biopsy specimen showed no immune deposits in the glomeruli, but fibronectin deposits were detected in the peripheral loop and mesangium by immunofluorescence. The basement membrane was intact. Twelve other family members subsequently were found to have some renal pathology. Renal function was preserved during 7 years of follow-up. The pathogenesis of fibronectin glomerulopathy is discussed.

[Five cases of acute poststreptococcal glomerulonephritis with acute renal failure and nephrotic syndrome].

During the period of 27 years from 1974 to 2000, acute episodes were studied retrospectively in 130 patients under 14 years of age with poststreptococcal acute glomerulonephritis(PSAGN). PSAGN cases have a variable clinical presentation from asymptomatic to severe oliguric acute renal failure(ARF). Proteinuria is nearly always present, but is less than 3.5 g/day. Nephrotic syndrome(NS) is not commonly observed in PSAGN. Among 130 patients, 5 cases had NS with ARF. The present study investigated a spectrum of NS with ARF and the significance of clinical features in PSAGN.