DGKE nephropathy as cause of atypical HUS

DGKE nephropathy is a form of atypical HUS (aHUS) with underlying genetic defect in DGKE gene encoding diacylglycerol kinase epsilon. The protein expresses in podocyte, endothelium and platelet and has role in regulating thrombogenesis. It may also maintain integrity of slit diaphragm in podocytes. Mutated DGKE  causes aHUS in early childhood with the disease manifests in first 2 year of life. In addition to thrombocytopenia, microangiopathic hemolytic anemia and renal injury, these patients had significant proteinuria, some in nephrotic range or nephrotic syndrome. Most patients experienced relapse in first few year of life with disease on more stable course later. Histopathology revealed chronic thrombotic microangiopathy with double contoured glomerular capillary walls with/without mesangial interposition. No active fibrin thrombi were identified.

Unlike complement-mediated aHUS, patients with DGKE nephropathy do not have mutation of or antibody to complement proteins. Therefore, it does not respond to treatment with eculizumab, an anticomplement drug. Patients who had renal transplant did not have recurrent disease. 

https://dx.doi.org/10.1038%2Fng.2590

https://dx.doi.org/10.1016%2Fj.kint.2020.01.045

Thrombotic microangiopathy in IgA nephropathy

Arteriosclerosis is a common finding in pathology of IgA nephropathy. Hypertension has been indicated as the cause of the arterial change. The chronic changes, ie. glomerulosclerosis, tubulointerstitial fibrosis, is implied as the cause of hypertension. However, prominent arteriosclerosis can be seen in biopsies with mild chronic changes.