From the *Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong; and †2010 Retina and Macula Centre, Kowloon, Hong Kong.
Asia Pac J Ophthalmol (Phila). 2016 Jul-Aug;5(4):245-52. doi: 10.1097/APO.0000000000000209.
Bietti crystalline dystrophy (BCD) is an inherited retinal degenerative disease characterized by crystalline deposits in the retina, followed by progressive atrophy of the retinal pigment epithelium (RPE), choriocapillaris, and photoreceptors. CYP4V2 has been identified as the causative gene for BCD. The CYP4V2 gene belongs to the cytochrome P450 superfamily and encodes for fatty acid ω-hydroxylase of both saturated and unsaturated fatty acids. The CYP4V2 protein is localized most abundantly within the endoplasmic reticulum in the RPE and is postulated to play a role in the physiological lipid recycling system between the RPE and photoreceptors to maintain visual function. Electroretinographic assessments have revealed progressive dysfunction of rod and cone photoreceptors in patients with BCD. Several genotypes have been associated with more severe phenotypes based on clinical and electrophysiological findings. With the advent of multimodal imaging with spectral domain optical coherence tomography, fundus autofluorescence, and adaptive optics scanning laser ophthalmoscopy, more precise delineation of BCD severity and progression is now possible, allowing for the potential future development of targets for gene therapy.
Bietti 结晶性营养不良症 (BCD) 是一种遗传性视网膜退行性疾病，其特征是视网膜内有结晶沉积，随后视网膜色素上皮 (RPE)、脉络膜毛细血管和光感受器进行性萎缩。CYP4V2 已被确定为 BCD 的致病基因。CYP4V2 基因属于细胞色素 P450 超家族，编码饱和和不饱和脂肪酸的脂肪酸 ω-羟化酶。CYP4V2 蛋白在 RPE 中的内质网中含量最丰富，据推测在 RPE 和光感受器之间的生理脂质再循环系统中发挥作用，以维持视觉功能。视网膜电图评估显示 BCD 患者的杆状和锥状光感受器逐渐出现功能障碍。根据临床和电生理发现，几种基因型与更严重的表型相关。随着频域光学相干断层扫描、眼底自发荧光和自适应光学扫描激光检眼镜等多种模态成像的出现，现在可以更精确地描绘 BCD 的严重程度和进展，为基因治疗的潜在目标开发提供了可能。
