A case of normolipidemic lipoprotein glomerulopathy due to the APOE Kyoto variant

We report a case of normolipidemic lipoprotein glomerulopathy (LPG) associated with the APOE Kyoto variant. A 54-year-old Chinese man was referred for evaluation of persistent low-level proteinuria detected on routine screening, with preserved renal function and no clinical features of nephrotic syndrome. Laboratory evaluation showed proteinuria without overt dyslipidemia. Extensive evaluation excluded secondary causes. Renal biopsy revealed markedly dilated capillary loops filled with characteristic lipoprotein thrombi, consistent with LPG. Subsequent genetic testing identified a heterozygous APOE c.127C>T (p.Arg43Cys) mutation, consistent with the APOE Kyoto variant. Because fasting lipid levels remained within reference ranges, lipid-lowering therapy was not initiated. Angiotensin receptor blockade was associated with a reduction in urine protein-to-creatinine ratio from 0.38 to 0.28 g/g over 2 months. This case broadens the phenotypic spectrum of APOE Kyoto-associated LPG by demonstrating biopsy-proven disease in the setting of largely normal systemic lipid levels.