Autosomal dominant polycystic kidney disease (ADPKD) patients with PKD1 mutations, particularly those with truncating mutations, show poor prognosis. However, the differences in disease progression with different mutation types are unclear. Here, a comparative study was conducted on the renal prognosis of patients with ADPKD who were categorized based on genotype (PKD1 versus PKD2 mutation), mutation type (truncating mutation: nonsense, frameshift, splicing mutation, and large deletion; non-truncating mutation: substitution and in-frame deletion), and mutation position. A total of 123 patients visiting our hospital were enrolled. Renal prognosis was poor for those with PKD1 splicing, PKD1 frameshift, and PKD2 splicing mutations. Despite the truncating mutation, the renal prognosis was relatively favorable for patients with nonsense mutations. Three out of five patients with PKD2 mutation required renal replacement therapy before 58 years of age. In conclusion, we showed that renal prognosis differs according to mutation types in both PKD1 and PKD2, and that it was favorable for those with nonsense mutations among patients with PKD1 truncating mutations. It was also confirmed that renal prognosis was not always favorable in patients with PKD2 mutations. A detailed assessment of mutation types may be useful for predicting the renal prognosis of patients with ADPKD.

We present two cases with steroid-resistant nephrotic syndrome (SRNS) and two cases with steroid-dependent nephrotic syndrome (SDNS) due to focal segmental glomerulonephritis (FSGS) who were treated with a single dose of rituximab (375 mg/m²). Although the two cases with SRNS showed no response, the two cases with SDNS achieved complete remission. The patients in whom the peripheral B-cell counts subsequently increased after the administration of rituximab demonstrated a relapse. Rituximab may be an effective treatment agent for SDNS with FSGS and the peripheral B-cell count may be a useful marker in such patients for preventing disease relapse.

Zebra bodies in kidney biopsy specimens are widely accepted as a specific feature of Fabry disease but they can also be present in a drug-induced mimic of Fabry disease, phospholipidosis. Chloroquine and hydroxychloroquine may both induce zebra body formation and kidney phospholipidosis. However, the frequency and clinical significance of such changes remain unknown. We report 5 serial kidney biopsy cases diagnosed as lupus nephritis during hydroxychloroquine administration. All 5 patients exhibited a few, but varying amounts, of zebra bodies in glomerular intrinsic cells, that is, podocytes, parietal epithelial cells, mesangial cells, and endothelial cells. Most of the zebra bodies detected were subtle, though certainly recognizable; these zebra bodies were much smaller than those observed in Fabry disease. Zebra bodies were not observed in patients with lupus nephritis in the absence of chloroquine or hydroxychloroquine administration. All patients with lupus nephritis who received hydroxychloroquine achieved complete remission during continuous use of hydroxychloroquine, though kidney toxicity of drug-induced phospholipidosis might be masked by immunosuppression. Based on this small series of cases, we speculate that the hydroxychloroquine-associated manifestation of zebra bodies and phospholipidosis in the kidney may be frequent phenomena and may have only a subclinical influence on kidney function, at least in the short term.

Whether the visceral-to-subcutaneous fat ratio (V/S ratio) is associated with renal prognosis in patients with chronic kidney disease (CKD) remains unclear. Furthermore, little is known about the effect of sex and the absolute amount of visceral fat accumulation such as visceral fat area (VFA) ≥100 cm² on the V/S ratio in relation to renal prognosis. In this study, 200 patients with CKD were evaluated for renal prognosis. Survival analyses and logistic regression analyses were conducted, generating time-series pseudo-R² values. The mean and percent change of the pseudo-R² values from the 6^th year to the 10^th year (6Y–10Y Mean and 6Y–10Y Change, respectively) were calculated for determining the cut-off points for the medium-term renal prognosis. Multivariate Cox regression analysis revealed that the V/S ratio was significantly associated with renal outcomes and that the VFA category (VFA ≥ 100 cm²) had significant interactions with the V/S ratio regarding renal prognosis. The hazard ratio (HR) of the V/S ratio was higher in the sub-cohort of VFA < 100 cm² than in the sub-cohort of VFA ≥ 100 cm² (HR: 6.42 vs. 1.00). Regarding sex differences, a strong association was noted between the V/S ratio and renal prognosis in women but not in men (HR: 2.40 vs. 1.10). On the other hand, 6Y–10Y Mean of the pseudo-R² values indicated differences in the cut-off points of the V/S ratio between men and women (V/S ratio: 0.75 vs. 0.5). Our findings indicate that it may be clinically meaningful to consider the differences in sex and the amount of VFA ≥100 cm² for the V/S ratio in relation to renal outcomes in patients with CKD. The 6Y–10Y Mean of the pseudo-R² values contributed to determining the cut-off points of the V/S ratio according to the sex difference.