The link between cystatin C and mortality independent of glomerular filtration rate (GFR) in adults has prompted the "Shrunken Pore Syndrome" (SPS) hypothesis, where high serum cystatin C with normal creatinine is explained by smaller glomerular pores, through which creatinine can pass freely, while the larger cystatin C, beta-trace protein (BTP) and pro-inflammatory molecules are retained. This study set out to apply the definition of SPS to children. In 294 children who underwent inulin clearance (Cin) test, serum creatinine, cystatin C and BTP were measured. For all three markers eGFRx was calculated using the full age spectrum equations. The ratio eGFRcys/eGFRcrea was plotted against the error of eGFRBTP(%) (i.e. eGFRBTP-Cin)/Cin*100%). Patients with and without SPS according to different cut-off points of eGFRcys/eGFRcrea and eGFRcys/Cin (i.e. ≤0.6,0.7,0.8) were compared in terms of eGFRx, Cin, error of eGFRx(%) and eGFRBTP/eGFRcrea-ratio. The ratio eGFRcys/eGFRcrea and error of eGFRBTP(%) were positively correlated. The prevalence of SPS by eGFRcys/eGFRcrea with a cut-off of 0.6 was 4.8%. Patients with SPS had a more negative error of eGFRcys(%) and eGFRBTP(%) and higher Cin regardless of the definition. Overestimation of eGFRcrea in patients with SPS was only present when using the eGFRcys/eGFRcrea rather than the eGFRcys/Cin definition. Cystatin C and BTP are related independent of creatinine, suggesting glomerular pore size as a common denominator. The prevalence of SPS in children is comparable to adults. For research in SPS, a definition based on eGFRcys/exogenous clearance study may be useful to study the effect of SPS on creatinine metabolism.

中文翻译：

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儿童收缩毛孔综合症的证据。

半胱氨酸蛋白酶抑制剂C和死亡率与成年人的肾小球滤过率（GFR）无关，这提示了“收缩毛孔综合症”（SPS）假说，其中较高的血清胱抑素C和正常肌酐可以通过较小的肾小球毛孔来解释，肌酐可以通过自由地保留较大的cystatin C，β-迹蛋白（BTP）和促炎分子。该研究旨在将SPS的定义应用于儿童。在294名接受菊粉清除率（Cin）测试的儿童中，测量了血清肌酐，胱抑素C和BTP。对于所有三个标记，使用完整的年龄谱方程计算eGFRx。将比率eGFRcys / eGFRcrea与eGFRBTP（％）的误差（即eGFRBTP-Cin）/ Cin * 100％）作图。根据eGFRx，ein，eGFRx（％）和eGFRBTP / eGFRcrea-ratio的eGFRx，Cin，eGFRx（％）的误差比较了根据eGFRcys / eGFRcrea和eGFRcys / Cin（即≤0.6、0.7、0.8）的不同临界点有无SPS的患者。eGFRcys / eGFRcrea的比率与eGFRBTP（％）的误差呈正相关。eGFRcys / eGFRcrea的SPS发生率为0.6％，为0.6。无论定义如何，SPS患者的eGFRcys（％）和eGFRBTP（％）的负误差更大，Cin更高。仅当使用eGFRcys / eGFRcrea而不是eGFRcys / Cin定义时，才出现SPS患者中eGFRcrea的高估。胱抑素C和BTP的相关性与肌酐无关，提示肾小球孔径是一个共同的指标。儿童中SPS的患病率与成人相当。对于SPS的研究，