Focal segmental glomerulosclerosis with a mutation in the mitochondrially encoded NADH dehydrogenase 5 gene: A case report.

NADH dehydrogenase 5 (ND5) is one of 44 subunits composed of Complex I in mitochondrial respiratory chain. Therefore, a mitochondrially encoded ND5 (MT-ND5) gene mutation causes mitochondrial oxidative phosphorylation (OXPHOS) disorder, resulting in the development of mitochondrial diseases. Focal segmental glomerulosclerosis (FSGS) which had podocytes filled with abnormal mitochondria is induced by mitochondrial diseases. An MT-ND5 mutation also causes FSGS. We herein report a Japanese woman who was found to have proteinuria and renal dysfunction in an annual health check-up at 29 years old. Because her proteinuria and renal dysfunction were persistent, she had a kidney biopsy at 33 years of age. The renal histology showed FSGS with podocytes filled with abnormal mitochondria. The podocytes also had foot process effacement and cytoplasmic vacuolization. In addition, the renal pathological findings showed granular swollen epithelial cells (GSECs) in tubular cells, age-inappropriately disarranged and irregularly sized vascular smooth muscle cells (AiDIVs), and red-coloured podocytes (ReCPos) by acidic dye. A genetic analysis using peripheral mononuclear blood cells and urine sediment cells detected the m.13513 G > A variant in the MT-ND5 gene. Therefore, this patient was diagnosed with FSGS due to an MT-ND5 gene mutation. Although this is not the first case report to show that an MT-ND5 gene mutation causes FSGS, this is the first to demonstrate podocyte injuries accompanied with accumulation of abnormal mitochondria in the cytoplasm.

Two cases of systemic lupus erythematosus complicated by hydronephrosis and unique small structures observed in the glomerular basement membrane.

We report two cases having a similar clinical profile of systemic lupus erythematosus (SLE) complicated by hydronephrosis that developed concurrently with a similar pathological recognition of numerous unique microspherical and microtubular structures in the glomerular basement membrane (GBM). Case 1 refers to a 29-year-old woman with SLE. An increase in the level of proteinuria had been triggered by hydronephrosis. The pathological findings of the kidney revealed "bubbling" of the GBM, microspherical and microtubular structures in the GBM, and a suspicion of podocytic infolding into the GBM. Case 2 refers to a 46-year-old woman with SLE complicated with hydronephrosis. The level of proteinuria had increased, which was followed by renal biopsy. Similar pathological findings detected in Case 1 were also recognized in Case 2. The renal disorder of the two cases exhibited pathological abnormality atypical of lupus nephritis. Histopathological abnormality similar to that detected in the two cases has rarely been reported until recently. The pathogenesis of the GBM lesions of the two cases has not yet been elucidated, but we believe that there is a possibility the persistent mild autoimmune disorder and the concurrence of an obstructive state of the urinary tract may facilitate the occurrence of the pathological abnormality, because the clinical feature of the two cases are conspicuously similar to each other.