背景:半胱氨酸尿症是一种罕见的遗传性疾病,其特征是胱氨酸的肾小管转运受损。临床特点主要包括肾结石及其并发症,尽管膀胱尿症患者可能存在其他合并症。目前没有关于胱氨酸尿症患者骨特征的数据。我们的目的是表征胱氨酸尿中的骨矿物质密度(BMD)。
方法:我们的研究包括在意大利的3个专科门诊就诊的估计肾小球滤过率(eGFR)≥60mL/min/1.73m2的成年膀胱尿症患者(罗马,那不勒斯和维罗纳)。在集中实验室中分析了骨转换的标志物。临床,生化和双能X线骨密度仪(DEXA)数据收集时间为2021年9月至2022年12月.线性回归模型用于评估Z得分与零的统计学显着偏差。
结果:27名患者被纳入研究。平均(SD)年龄为37(15)岁,41%是女性。平均估计肾小球滤过率为99mL/min/1.73m2。与骨转换相关的血清参数(甲状旁腺激素,FGF23,钙和磷酸盐)均在正常范围内,只有4例患者出现轻度低磷血症。低骨密度的患病率,定义为任何地点的Z分数≤-2,是15%。大多数站点的平均Z得分为负。
结论:我们的研究表明,与相同性别和年龄的个体相比,膀胱尿症患者的骨矿物质密度较低,即使他们的肾功能正常.
BACKGROUND: Cystinuria is a rare genetic disease characterized by impaired tubular transport of cystine. Clinical features of
cystinuria mainly include nephrolithiasis and its complications, although cystinuric patients may present with other comorbidities. There are currently no data on bone features of patients with
cystinuria. Our aim is to characterize bone mineral density (BMD) in
cystinuria.
METHODS: Our study included adult cystinuric patients with estimated glomerular filtration rate (eGFR) ≥ 60 mL/min/1.73 m2 followed at 3 specialized outpatient clinics in Italy (Rome, Naples and Verona). Markers of bone turnover were analyzed in a centralized laboratory. Clinical, biochemical and dual-energy X-ray absorptiometry (DEXA) data were collected from September 2021 to December 2022. Linear regression models were used to evaluate statistically significant deviations from zero of Z-scores.
RESULTS: Twenty-seven patients were included in the study. Mean (SD) age was 37 (15) years, 41% were women. Mean estimated glomerular filtration rate was 99 mL/min/1.73 m2. Serum parameters associated with bone turnover (parathyroid hormone, FGF23, calcium and phosphate) were all in the normal range, with only 4 patients showing mild hypophosphatemia. Prevalence of low bone mineral density, defined as Z-score ≤ - 2 at any site, was 15%. Average Z-scores were negative across most sites.
CONCLUSIONS: Our study suggests that cystinuric patients have lower bone mineral density compared with individuals of the same sex and age, even when their kidney function is normal.