Précis Cystinosis is a lysosomal storage disease leading to an accumulation of cystine crystals in several organs. We aim to comprehensively describe chorioretinal cystine crystals via spectral domain optical coherence tomography (SD-OCT) and elaborate a new biomarker for systemic disease control. Background/aims Cystinosis is a rare lysosomal storage disease leading to an accumulation of cystine crystals in several organs. This study aims to describe the deposition of retinochoroidal crystals in infantile nephropathic cystinosis and to elucidate their potential value as an objective biomarker for systemic disease control. Methods This cross-sectional study was carried out by the University Eye Hospital of the Ludwig-Maximilian University (Munich, Germany) in collaboration with the German Cystinosis Study Group. A complete ophthalmologic examination was performed, along with posterior segment SD-OCT (Spectralis; Heidelberg Engineering GmbH, Heidelberg, Germany). Retinochoroidal crystals were graded by employing a novel semiquantitative grading system—the retinochoroidal cystine crystal score (RCCCS). To quantify quality of vision, patients completed a specific questionnaire. A total of 85 eyes of 43 patients with cystinosis were included (mean age 22.3±8.8 years, range 6–39; male:female ratio=23:20). Results Cystine crystals were detectable in all neuroretinal layers and the choroid, most frequently in the choriocapillaris. The RCCCS was negatively correlated with cysteamine intake (r=0.533, p=0.001) and positively with cystatin C, a stable parameter of renal function (r=0.496, p=0.016). Moreover, the value of the RCCCS affected subjective quality of vision. Genetic analysis indicated pronounced crystal deposition in patients with heterozygous mutations containing the 57-kb-deletion allele of the CTNS gene. Conclusion Ocular cystinosis leads to retinochoroidal crystal accumulation in every stage of the disease. Crystal deposition may be markedly influenced by oral cysteamine therapy. Therefore, the presented SD-OCT based grading system might serve as an objective biomarker for systemic disease control. Data are available in a public, open access repository. Repository name: The Open Science framework URL:

中文翻译：

---

基于光谱域光学相干断层扫描的视网膜脉络膜胱氨酸晶体评分：婴儿肾病性胱氨酸病的一个窗口

Précis Cystinosis 是一种溶酶体贮积病，导致胱氨酸晶体在多个器官中积累。我们的目标是通过光谱域光学相干断层扫描 (SD-OCT) 全面描述脉络膜视网膜胱氨酸晶体，并阐述一种用于系统性疾病控制的新生物标志物。背景/目的 胱氨酸贮积症是一种罕见的溶酶体贮积病，可导致胱氨酸晶体在多个器官中积聚。本研究旨在描述视网膜脉络膜晶体在婴儿肾病性胱氨酸病中的沉积，并阐明它们作为全身性疾病控制的客观生物标志物的潜在价值。方法 本横断面研究由路德维希-马克西米利安大学眼科医院（德国慕尼黑）与德国胱氨酸病研究小组合作开展。进行了完整的眼科检查以及眼后节 SD-OCT（Spectralis；海德堡工程有限公司，德国海德堡）。视网膜脉络膜晶体采用一种新型半定量分级系统——视网膜脉络膜胱氨酸晶体评分 (RCCCS) 进行分级。为了量化视力质量，患者完成了一份特定的调查问卷。共纳入 43 例胱氨酸病患者的 85 只眼（平均年龄 22.3±8.8 岁，范围 6-39；男女比例 = 23:20）。结果 在所有神经视网膜层和脉络膜中都可检测到胱氨酸晶体，最常见于脉络膜毛细血管。RCCCS 与半胱胺摄入量呈负相关 (r=0.533, p=0.001)，与肾功能稳定参数胱抑素 C 呈正相关 (r=0.496, p=0.016)。而且，RCCCS 的值影响视觉的主观质量。遗传分析表明，在含有 CTNS 基因 57-kb 缺失等位基因的杂合突变患者中有明显的晶体沉积。结论 眼部胱氨酸病在疾病的各个阶段均导致视网膜脉络膜结晶堆积。晶体沉积可能会受到口服半胱胺疗法的显着影响。因此，所提出的基于 SD-OCT 的分级系统可以作为全身疾病控制的客观生物标志物。数据可在公共、开放访问的存储库中获得。存储库名称：开放科学框架 URL：结论 眼部胱氨酸病在疾病的各个阶段均导致视网膜脉络膜结晶堆积。晶体沉积可能会受到口服半胱胺疗法的显着影响。因此，所提出的基于 SD-OCT 的分级系统可以作为全身疾病控制的客观生物标志物。数据可在公共、开放访问的存储库中获得。存储库名称：开放科学框架 URL：结论 眼部胱氨酸病在疾病的各个阶段均导致视网膜脉络膜结晶堆积。晶体沉积可能会受到口服半胱胺疗法的显着影响。因此，所提出的基于 SD-OCT 的分级系统可以作为全身疾病控制的客观生物标志物。数据可在公共、开放访问的存储库中获得。存储库名称：开放科学框架 URL：