Fuchs S, Nakazawa M, Maw M, Tamai M, Oguchi Y, Gal A
Institut für Humangenetik, Universitäts-Krankenhaus Eppendorf, Hamburg, Germany.
Nat Genet. 1995 Jul;10(3):360-2. doi: 10.1038/ng0795-360.
Oguchi disease is a rare autosomal recessive form of congenital stationary night blindness with all other visual functions, including visual acuity, visual field, and colour vision being usually normal. A typical clinical feature of the disorder is a golden or gray-white discolouration of the fundus which disappears in the dark-adapted state and reappears shortly after the onset of light ('Mizuo phenomenon'; Fig. 1). The course of dark adaptation of rod photoreceptors is extremely retarded in Oguchi disease while that of cones appears to proceed normally. The locus for Oguchi disease was recently mapped between D2S172 and D2S345 on distal chromosome 2q by linkage analysis. Interestingly, the gene for arrestin, an intrinsic rod photoreceptor protein implicated in the recovery phase of light transduction, also maps to this region of chromosome 2q (refs 6, 7). Here we report that in five out of six unrelated Japanese patients with Oguchi disease, we have identified a homozygous deletion of nucleotide 1147 (1147delA) in codon 309 of the arrestin gene, predicting a shift in the reading frame and a premature termination of translation which may result in 'functional null alleles.'
小口病是一种罕见的常染色体隐性先天性静止性夜盲症，患者的所有其他视觉功能，包括视力、视野和色觉通常均正常。该疾病的一个典型临床特征是眼底出现金色或灰白色变色，在暗适应状态下消失，在光照开始后不久又重新出现（“水尾现象”；图1）。在小口病中，视杆光感受器的暗适应过程极度延迟，而视锥光感受器的暗适应过程似乎正常进行。最近通过连锁分析将小口病的基因座定位在2号染色体长臂远端的D2S172和D2S345之间。有趣的是，视紫红质抑制蛋白基因也定位于2号染色体长臂的这一区域，视紫红质抑制蛋白是一种视杆光感受器内在蛋白，参与光转导的恢复阶段（参考文献6、7）。在此我们报告，在6名不相关的日本小口病患者中，有5名患者的视紫红质抑制蛋白基因第309密码子处发生了1147位核苷酸的纯合缺失（1147delA），预计这会导致阅读框移位和翻译提前终止，可能产生“功能性无效等位基因”。
