Department of Ophthalmology, Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA.
Doc Ophthalmol. 2021 Aug;143(1):75-83. doi: 10.1007/s10633-021-09820-4. Epub 2021 Feb 6.
Galloway-Mowat syndrome (GAMOS) is a clinically heterogenous and rare condition classically described as the combination of nephrotic syndrome associated with brain anomaly and delays in development. It was first reported in the literature in 1968 by Galloway W.H and Mowat A.P. Reports of visual anomaly in these patients are generally limited to decreased visual acuity, nystagmus and optic nerve atrophy. To this day, little is known about retinal function in this disease. Therefore, the purpose of this case report is to reveal abnormal retinal function (including light-adapted and dark-adapted retinal function) in a female patient diagnosed with GAMOS due to mutation of the WDR73 gene.
Complete dilated pediatric ophthalmic examination and ISCEV full field standard light (10 min of light adaptation; background light: 30 cd.m; flash intensity: 3.0 cd.sec.m) and dark-adapted (20 min of dark adaptation; flash intensities: 0.01, 3.0 and 10.0 cd.sec.m) electroretinograms were performed on a 2-year-old female patient diagnosed with GAMOS due to a biallelic mutation in the WDR73 gene.
Ophthalmologic evaluation under anesthesia revealed normal appearing anterior segments. Significant bilateral optic nerve pallor was noted. Fundus examination appeared to be abnormal and demonstrated mid-peripheral whitish glistening appearance with possible gliosis. Retinoscopy revealed bilateral high myopia with a refractive error of -8.00 sphere in both eyes. ISCEV standard ERG revealed residual responses under light-adapted condition. Undetectable responses were obtained after 20 min of dark adaptation when using a dim flash (DA 0.01). However, when brighter flashes were used in a dark-adapted condition (DA 3.0 and DA 10.0), the ERGs were detectable, albeit abnormal in amplitudes and of electronegative morphology.
The results obtained showed significant retinal functional deficit affecting both the cone and the rod photoreceptor pathways, along with the inner retina, in a patient diagnosed with GAMOS due to biallelic mutations in the WDR73 gene. Our report is limited to one patient, and additional studies are needed to verify whether retinal functional anomalies, as measured by the full field electroretinogram, present a novel biomarker in all patients affected with GAMOS or only in patients with a mutation in the WDR73 gene. Given the evidence of retinal functional changes presented in this study, it is strongly suggested to include complete ophthalmic examination, retinal imaging, including OCT, and full field ERG testing in patients affected with GAMOS.
Galloway-Mowat 综合征（GAMOS）是一种临床异质性和罕见的疾病，其特征通常是肾病综合征合并脑异常和发育迟缓。它于 1968 年由 Galloway W.H 和 Mowat A.P 首次在文献中报道。这些患者的视觉异常一般限于视力下降、眼球震颤和视神经萎缩。迄今为止，人们对这种疾病的视网膜功能知之甚少。因此，本病例报告的目的是揭示一名女性 GAMOS 患者的视网膜功能异常（包括明适应和暗适应视网膜功能），该患者的基因突变是 WDR73 基因。
对一名 2 岁女性患者进行全面散瞳小儿眼科检查和 ISCEV 全视野标准光（10 分钟明适应；背景光：30cd.m；闪光强度：3.0cd.sec.m）和暗适应（20 分钟暗适应；闪光强度：0.01、3.0 和 10.0cd.sec.m）视网膜电图检查，该患者被诊断为 GAMOS，原因是 WDR73 基因的双等位基因突变。
麻醉下的眼科评估显示前节正常。双侧明显视神经苍白。眼底检查似乎异常，表现为中周部灰白色闪烁外观，可能有神经胶质增生。检眼镜检查显示双眼高度近视，双眼球镜屈光度均为-8.00。ISCEV 标准 ERG 在明适应条件下显示残留反应。当使用弱闪光（DA 0.01）进行 20 分钟暗适应时，无法获得反应。然而，当在暗适应条件下使用更亮的闪光（DA 3.0 和 DA 10.0）时，ERG 是可检测的，尽管振幅异常，且形态呈电阴性。
本研究结果表明，一名被诊断为 GAMOS 的患者的双眼均存在显著的视网膜功能缺陷，影响视锥和视杆光感受器通路以及内视网膜，该患者存在 WDR73 基因突变的双等位基因突变。我们的报告仅限于一名患者，需要进一步研究以验证全视野视网膜电图测量的视网膜功能异常是否在所有 GAMOS 患者中或仅在 WDR73 基因突变患者中作为一种新的生物标志物。鉴于本研究中呈现的视网膜功能变化证据，强烈建议在患有 GAMOS 的患者中进行全面的眼科检查、视网膜成像（包括 OCT）和全视野 ERG 测试。
