Diagnosis of Kidney Diseases of Unknown Etiology Through Biopsy-Genetic Analysis.

Introduction: Previous studies have suggested that genetic kidney diseases in adults are often overlooked, representing up to 10% of all cases of chronic kidney disease (CKD). We present data obtained from exome sequencing (ES) analysis of patients with biopsy-proven undetermined kidney disease (UKD). Methods: ES was proposed during routine clinical care in patients with UKD from January 2020 to December 2021. We used in silico custom kidney genes panel analysis to detect pathological variations using American College of Medical Genetics guidelines in 52 patients with biopsy-proven UKD with histological finding reassessment. Results: We detected 12 monogenic renal disorders in 21 (40.4%) patients. The most common diagnoses were collagenopathies (8/21,38.1%), COL4A3 and COL4A4 accounting for 80% of these diagnoses, and ciliopathies (5/21, 23.8%). The diagnostic yield of ES was higher in female patients and patients with a family history of kidney disease (57.1% and 71%, respectively). Clinical nephropathy categories matched with the final genetic diagnoses in 72.7% of cases, whereas histological renal lesions matched with the final diagnoses in 92.3% of cases. The genetics diagnoses and histopathological findings were in complete agreement for both glomerular and tubulointerstitial cases. Interstitial inflammation without tubulitis was only observed in tubulopathies or ciliopathies. Isolated CKD, CKD with proteinuria or hematuria, and isolated proteinuria or hematuria yielded the highest diagnostic yields (54.6%, 52.6%, and 42.9%, respectively). Conclusion: ES done in patients with biopsy-proven UKD should be considered as a first-line tool for CKD patients with a family history of kidney disease. Combination of ES and kidney biopsy may have major impacts on kidney disease ontology.

IgA Vasculitis With Underlying Liver Cirrhosis: A French Nationwide Case Series of 20 Patients.

OBJECTIVE: Immunoglobulin A vasculitis (IgAV) and nephropathy (IgAN) share common immunological mechanisms. Liver cirrhosis is well known to be associated with IgAN. Here, we aimed to describe the presentation and outcome of IgAV patients with underlying cirrhosis. METHODS: We conducted a French nationwide retrospective study of adult patients presenting with both IgAV and cirrhosis. Baseline characteristics were compared to those of the 260 patients included in the French nationwide IgAV registry (IGAVAS). RESULTS: Twenty patients were included, and 7 (35%) were female. The mean ± SD age was 62.7 ± 11 years. At baseline, compared with IGAVAS patients, patients with underlying cirrhosis were older (62.7 ± 11 vs 50.1 ± 18, P < 0.01) and displayed more constitutional symptoms (weight loss 25% vs 8%, P = 0.03). Patients with underlying cirrhosis were also more likely to exhibit elevated serum IgA levels (5.6 g/L vs 3.6 g/L, P = 0.02). Cirrhosis and IgAV were diagnosed simultaneously in 12 patients (60%). Cirrhosis was mainly related to alcohol intake (n = 15, 75%), followed by nonalcoholic steato-hepatitis (n = 2), chronic viral hepatitis (n = 1), hemochromatosis (n = 1), and autoimmune hepatitis (n = 1). During follow-up with a median of 17 months (IQR 12-84), 10/13 (77%) exhibited IgAV remission at Month 3. One patient presented a minor relapse. Six patients died, but no deaths were related to IgAV. CONCLUSION: We report the first case series of IgAV patients with underlining cirrhosis, to our knowledge, which was mainly alcohol related. The liver disease did not seem to affect baseline vasculitis characteristics. Physicians should investigate the existence of liver cirrhosis at IgAV diagnosis, especially in the context of alcohol abuse.

First phenotypic description of a female patient with c.610 T > C variant of GLA: a renal-predominant presentation of Fabry disease.

BACKGROUND: Fabry disease (FD) is an X-linked lysosomal storage disorder due to deficient alpha-galactosidase activity leading to intracellular glycosphingolipid accumulation. Multiple variants have been reported in the GLA gene coding for alpha-galactosidase, and the question of the pathogenicity of rare variants needs to be addressed, especially in patients with mild phenotypes. CASE PRESENTATION: The patient, a 37-year-old female, presented with a persistent proteinuria after an otherwise uncomplicated first pregnancy. Renal biopsy showed both mild mesangial IgA deposits, and a striking vacuolization of podocytes and tubular cells consistent with Fabry disease. On electron microscopy, discrete but characteristic pseudo-myelinic lamellar inclusions were observed in the podocytes' lysosomes. A more detailed physical examination revealed an angiokeratoma, and medical history ancient acroparesthesia. There was no cardiac or cerebral involvement of Fabry disease on magnetic resonance imaging. While blood enzymatic activity of alpha-ga lactosidase was normal in this patient, lysoGb3 was elevated (3 N), and a rare heterozygous variant called c.610 T > C was documented in GLA gene. The patient was treated with an ACE inhibitor, with a rapid decrease in proteinuria. After a 5-year follow-up, her renal function has remained normal, with mild proteinuria, and normal cardiac echography. CONCLUSIONS: We report and phenotypically describe the first case of a Fabry disease female patient carrying the GLA c.610 T > C variant associated with a renal-predominant clinical presentation.