Purpose To qualitatively and quantitatively characterise the genotypes and phenotypes of Bietti’s crystalline dystrophy (BCD) in a cohort of patients. Design Cross-sectional and observational study. Methods Clinically confirmed BCD patients were recruited for genotyping and phenotyping. Multiple retinal imaging modalities were employed. Atrophy in the fovea was adopted as major consideration for staging strategy, while percentage area of autofluorescence (AF) atrophy (PAFA) in the macula was determined for quantitation. Results In 74 clinically diagnosed BCD patients, c.802–8_810del17insGC was shown the predominant variant of the CYP4V2 gene (allele frequency 55.4%). Sixty-two cases (123 eyes) with full imaging data were classified according to a modified criterion into stages 1 (n=8, 6.50%), 2A (n=9, 7.32%), 2B (n=17, 13.82%), 3A (n=30, 24.39%) and 3B (n=59, 47.97%). The eyes of the stage 2B were particularly deemed ‘high risk’ due to atrophy near fovea, while in stage 3A, though with remarkable foveal atrophy, preserved retinal pigment epithelium/photoreceptor islands near the fovea were found in 14 eyes. A tendency of increase in PAFA with age was found (rs=0.31, p=0.014). Significant PAFA increase was shown through stages 1 to 3B, and best-corrected visual acuity (BCVA, Logarithm of the Minimum Angle of Resolution) was shown to moderately correlate with PAFA (rs=0.56, p<0.001). Conclusion The PAFA might be an efficient biomarker for BCD severities correlating with BCVA. The highly heterogeneous chorioretinopathy and BCVA of BCD cases appear to be associated with disease stages, progression types and patients’ ages. Foveal involvement should be of a major concern for consideration of potential therapeutic intervention. Data are available upon reasonable request. All data relevant to the study are included in the article or uploaded as supplementary information.

中文翻译：

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Bietti 晶体营养不良：基因分型以及深度定性和定​​量表型分析，为临床试验做准备


目的 定性和定量描述一组患者中 Bietti 晶体营养不良 (BCD) 的基因型和表型。设计横断面和观察研究。方法 招募临床确诊的BCD患者进行基因分型和表型分析。采用多种视网膜成像方式。中央凹萎缩被作为分期策略的主要考虑因素，同时确定黄斑中自发荧光（AF）萎缩（PAFA）面积的百分比以进行定量。结果 在 74 名临床诊断的 BCD 患者中，c.802–8_810del17insGC 被证明是 CYP4V2 基因的主要变异（等位基因频率为 55.4%）。 62例（123只眼）具有完整影像学数据，根据修改后的标准分为1期（n=8，6.50%）、2A期（n=9，7.32%）、2B期（n=17，13.82%） 、3A（n=30，24.39%）和 3B（n=59，47.97%）。 2B 阶段的眼睛由于中央凹附近的萎缩而被特别视为“高风险”，而在 3A 阶段，尽管中央凹萎缩明显，但在 14 只眼睛中发现了中央凹附近保留的视网膜色素上皮/光感受器岛。发现PAFA随着年龄的增长而增加的趋势（rs=0.31，p=0.014）。从第 1 阶段到第 3B 阶段，PAFA 显着增加，最佳矫正视力（BCVA，最小分辨角度的对数）与 PAFA 中度相关（rs=0.56，p<0.001）。结论 PAFA 可能是与 BCVA 相关的 BCD 严重程度的有效生物标志物。 BCD 病例的高度异质性脉络膜视网膜病变和 BCVA 似乎与疾病分期、进展类型和患者年龄相关。中心凹受累应该是考虑潜在治疗干预的主要关注点。数据可根据合理要求提供。 与研究相关的所有数据都包含在文章中或作为补充信息上传。