A case of non-lupus full-house nephropathy diagnosed by kidney biopsy but observed IgA nephropathy on second biopsy.

We describe a case of full-house nephropathy without any underlying disease, including systemic lupus erythematosus. A 40-year-old woman was referred to our hospital with mild proteinuria and microscopic hematuria. The patient was diagnosed with immune complex-mediated glomerulonephritis with a predominant mesangioproliferative pattern based on renal histopathological results using full-house immunofluorescence staining. She showed no clinical criteria for the diagnosis of systemic lupus erythematosus, except for kidney disorders, and tested negative for antinuclear antibodies throughout her clinical course. However, in the second kidney biopsy, no C1q or C4 were detected in the immunofluorescence study, suggesting an immunoglobulin A nephropathy-like pattern. The patient responded favorably to corticosteroid treatment. We found a heterozygous CFHR3-CFHR1 deletion. The association between full-house nephropathy and CFHR3-CFHR1 deletion is unknown, but its influence on the histological pattern in our case is suspected. This indicates the diversity in the pathogenesis of non-lupus full-house nephropathy and warrants further investigation.

Copy number variation analysis using next-generation sequencing identifies the CFHR3/CFHR1 deletion in atypical hemolytic uremic syndrome: a case report.

OBJECTIVES: Atypical hemolytic uremic syndrome (aHUS) is characterized by a triad of thrombocytopenia, microangiopathic hemolytic anemia, and acute renal failure resulting from platelet thrombi in the microcirculation of the kidney and other organs, in the absence of a preceding diarrheal illness. This report describes a case in which copy number variation (CNV) analysis using next-generation sequencing (NGS) identified the CFHR3/CFHR1 deletion in a patient with aHUS. METHODS: A 49-year-old Korean female was diagnosed with aHUS based on clinical findings, including schistocytes in peripheral blood and marked thrombocytopenia, suggesting the presence of thrombotic microangiopathy, elevated serum lactate dehydrogenase, and acute kidney injury. Sequence variants and CNV generated from NGS data were estimated to determine if there was a potential genetic cause. Multiplex ligation-dependent probe amplification (MLPA) was conducted to confirm the CFHR3/CFHR1 deletion identified by NGS with CNV analysis. RESULTS: No known or novel pathogenic single nucleotide variant or small insertion/deletion that would be predicted to have damaging effects that could lead to aHUS were identified. However, CNV analysis of NGS data identified the heterozygous CFHR3/CFHR1 deletion. MLPA confirmed this loss of one copy number between the CFHR3 and the CFHR1 genes on chromosome 1q31.3. CONCLUSION: We genetically diagnosed a Korean woman harboring a heterozygous CFHR3/CFHR1 deletion of a known causative gene for aHUS. Our report emphasizes the need for CNV analysis of NGS data and gene dosage assays, such as MLPA, to evaluate large-scale deletions or duplications and generate hybrid CFH genes in patients with suspected aHUS.

Atypical hemolytic uremic syndrome after childbirth: a case report.

We report a case of atypical hemolytic uremic syndrome (HUS) that occurred after childbirth. A 33-year-old female was admitted to the emergency room, complaining of abdominal pain six days after giving birth to twins. The patient was diagnosed with hemoperitoneum due to hepatic hemangioma rupture and a left lateral hepatectomy was performed. Angioembolization was performed for the accompanying uterine artery bleeding. After that, her kidney function worsened after the 12th day postpartum. Microangiopathic anemia, thrombocytopenia and renal dysfunction were observed. Shiga toxin-producing Escherichia coli was negative in the stool. Plasma ADMATS 13 activity was normal. After transfer to the nephrology department with suspected atypical HUS, the patient underwent fresh frozen plasma (FFP) transfusion with three hemodialysis sessions. The patient improved without additional dialysis, but a renal biopsy was performed because of persistent proteinuria. Renal pathologic findings were compatible with thrombotic microangiopathy. A genetic test for atypical HUS revealed variants of uncertain significance in the complement factor H related (CFHR) 4 gene and the presence of CFHR3-CFHR1 copy number gain. The CFHR3-CFHR1 copy number gain found in this case is a rare causative mutation of atypical HUS. This case suggests that genetic testing of atypical HUS should include analysis of CFH-CFHR rearrangements as well as general screening for complement-associated genes.