Al Oreany Abdulaziz Abdulrahman, Al Hadlaq Abdulaziz, Schatz Patrik
Vitreoretinal Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia.
Department of Ophthalmology, Clinical Sciences, Scane County University Hospital, University of Lund, Lund, Sweden.
Graefes Arch Clin Exp Ophthalmol. 2016 Oct;254(10):1951-1956. doi: 10.1007/s00417-016-3346-6. Epub 2016 Apr 15.
To describe congenital stationary night blindness (CSNB) with negative electroretinogram, hypoplastic discs, nystagmus and thinning of the inner nuclear layer (INL).
Retinal structure was analyzed qualitatively with spectral domain optical coherence tomography and wide field imaging. Retinal function was evaluated with full-field electroretinography (ffERG). Molecular genetic testing included next-generation sequencing (NGS) of the known genes involved in CSNB.
Patients presented with CSNB presented with nystagmus, high myopia, hypoplastic discs and negative ffERG with no measurable rod response. The retinas appeared normal and automated segmentation of retinal layers demonstrated a relative reduction of thickness of the INL. There was no significant change in the ffERG after prolonged 2 hour dark adaptation compared to standard 30 minute dark adaptation. Affected family members harboured the homozygous 1-bp deletion c.2394delC in exon 18 of the TRPM1 gene, whereas their unaffected parents were heterozygous carriers.
This data expands the genotype and phenotype spectrum of CSNB. The lack of improvement of rod responses after prolonged dark adaptation, together with thinning of the INL, is compatible with postreceptoral transmission dysfunction in the bipolar cells. Such knowledge may prove useful in future development of treatment for outer retinal dystrophies, using opsin genes to restore light responses in survivor neurons in the inner retina.
描述伴有视网膜电图阴性、视盘发育不全、眼球震颤及内核层（INL）变薄的先天性静止性夜盲（CSNB）。
采用光谱域光学相干断层扫描和广域成像对视网膜结构进行定性分析。用全视野视网膜电图（ffERG）评估视网膜功能。分子遗传学检测包括对已知与CSNB相关基因的二代测序（NGS）。
患有CSNB的患者表现为眼球震颤、高度近视、视盘发育不全及ffERG阴性，无可测量的视杆反应。视网膜外观正常，视网膜层的自动分割显示INL厚度相对减小。与标准30分钟暗适应相比，2小时长时间暗适应后ffERG无显著变化。受影响的家庭成员在TRPM1基因第18外显子中存在纯合的1个碱基缺失c.2394delC，而其未受影响的父母为杂合携带者。
这些数据扩展了CSNB的基因型和表型谱。长时间暗适应后视杆反应缺乏改善，以及INL变薄，与双极细胞的感受器后传递功能障碍相符。这些知识可能在未来治疗外层视网膜营养不良的发展中有用，即利用视蛋白基因恢复视网膜内层存活神经元的光反应。
