Early-onset lipoprotein glomerulopathy in a 23-month-old boy with homozygous APOE Kyoto variant.

Abstract

Lipoprotein glomerulopathy is a rare, inherited kidney disorder caused by pathogenic APOE variants that leads to obstruction of glomerular capillaries by lipoprotein thrombi, steroid-resistant nephrotic syndrome, and progressive chronic kidney disease. Immunosuppressive therapy is ineffective; instead, lipid-lowering measures reduce intraglomerular lipoprotein deposition and preserve kidney function. We describe a 23-month-old boy presenting with nephrotic syndrome and severe anaemia. Family history of kidney disease, parental consanguinity, and ultrasound showing enlarged echogenic kidneys led to early renal biopsy, which confirmed lipoprotein glomerulopathy. Genetic analysis revealed homozygosity for the APOE Kyoto variant and prompted discontinuation of prednisolone. Initiation of lipid-lowering therapy resulted in rapid clinical improvement. This case highlights the phenotype associated with homozygous APOE Kyoto variant and demonstrates how prompt kidney biopsy and genetic testing in atypical paediatric nephrotic syndrome can enable targeted treatment.