Wang Wenji, Chen Lin, Ding Feng, Li Xuezhu
Division of Nephrology, Shanghai Ninth People's Hospital, School of Medicine, Shanghai JiaoTong University, Shanghai, 200011, China.
BMC Nephrol. 2025 May 15;26(1):242. doi: 10.1186/s12882-025-04170-8.
Autosomal dominant polycystic kidney disease (ADPKD) is the most frequent monogenic polycystic kidney disorder, but ADPKD presented as Glomerulocystic kidney (GCK) in adults is uncommon. Thin basement membrane nephropathy (TBMN) seems to account for major causes of familial hematuria and can coexist with other glomerular diseases. Here, we report a case of atypical manifestation of ADPKD presenting as GCK superimposed with TBMN in an adult man.
A 40-year-old male presented with moderate proteinuria, microhematuria and renal insufficiency. He has no family history of kidney disease. Ultrasound revealed slightly enlarged kidneys with echogenic cortex. 2 to 3 visible small cortical cysts on both kidneys, and no anatomical abnormalities were detected by CT scan. Renal biopsy demonstrated that 33.3% (9/27) of the glomeruli had marked dilatation of Bowman's space. The glomerular cysts were lined by a simple layer of cuboidal epithelium, which was stained positive for Claudin-1 (parietal epithelial cell marker), but negative for LTA and DBA (tubular epithelial cell markers). There were foci of mild chronic interstitial fibrosis with few inflammatory infiltrates. Immunofluorescence stains were negative. Transmission Electron microscopy (TEM) revealed extensive glomerular basement membrane (GBM) thinning, without splitting or lamellation. The average thickness of GBM was 221 ± 25 nm. No electron dense deposits were identified by TEM. The next-generation sequencing indicated pathogenic heterozygous deletion of PKD1 exon 3, and the mutation was determined to be a de novo mutation by familial variant analysis. No pathogenic mutations of COL4A3, COL4A4, COL4A5, UMOD, TCF2 and HNF1β were identified.
We report a rare case of atypical ADPKD presenting as GCK superimposed with TBMN. GCK is a rare disease and often overlooked. It is important for practicing nephrologists to have a clear understanding of GCK. GCK involves in various conditions, thus genetic analysis should be considered.
常染色体显性多囊肾病（ADPKD）是最常见的单基因多囊肾病，但成人期表现为肾小球囊性肾病（GCK）的ADPKD并不常见。薄基底膜肾病（TBMN）似乎是家族性血尿的主要病因，且可与其他肾小球疾病共存。在此，我们报告一例成年男性ADPKD表现为GCK并叠加TBMN的非典型病例。
一名40岁男性，表现为中度蛋白尿、镜下血尿和肾功能不全。他无肾病家族史。超声显示双肾轻度增大，皮质回声增强。双肾可见2至3个小的皮质囊肿，CT扫描未发现解剖结构异常。肾活检显示33.3%（9/27）的肾小球鲍曼囊明显扩张。肾小球囊肿内衬单层立方上皮，Claudin-1（壁层上皮细胞标志物）染色阳性，但LTA和DBA（肾小管上皮细胞标志物）染色阴性。有轻度慢性间质纤维化灶，炎症浸润较少。免疫荧光染色阴性。透射电子显微镜（TEM）显示广泛的肾小球基底膜（GBM）变薄，无分裂或分层。GBM平均厚度为221±25nm。TEM未发现电子致密沉积物。二代测序显示PKD1外显子3存在致病性杂合缺失，经家系变异分析确定该突变为新发突变。未发现COL4A3、COL4A4、COL4A5、UMOD、TCF2和HNF1β的致病性突变。
我们报告了一例罕见的非典型ADPKD，表现为GCK并叠加TBMN。GCK是一种罕见疾病，常被忽视。临床肾病学家清楚了解GCK很重要。GCK涉及多种情况，因此应考虑进行基因分析。
