Serfozo Csilla, Barta Andras Gellert, Horvath Endre, Sumanszki Csaba, Csakany Bela, Resch Miklos, Nagy Zoltan Zsolt, Reismann Peter
Department of Ophthalmology, Faculty of Medicine, Semmelweis University, Maria utca 39, Budapest 1085, Hungary.
Department of Internal Medicine and Oncology, Faculty of Medicine, Semmelweis University, Koranyi Sandor utca 2/a, Budapest 1083, Hungary.
Mol Genet Metab Rep. 2020 Sep 22;25:100649. doi: 10.1016/j.ymgmr.2020.100649. eCollection 2020 Dec.
Retinal changes are poorly described in early treated phenylketonuria (ETPKU). We aimed to investigate possible visual functional and ocular microstructural changes in adult patients with ETPKU. Optical coherence tomography (OCT) and its angiography (OCTA) data from patients with PKU were compared to healthy controls.
In this prospective, monocentric, cross-sectional, case-control study 50 patients with ETPKU and 50 healthy subjects were evaluated with OCT and OCTA. Measurements were performed on right eyes. The following visual function parameters were studied: best corrected visual acuity (BCVA), spherical equivalent (SE), contrast sensitivity and near stereoacuity; microstructural parameters: retinal nerve fiber layer thickness (RNFLT), ganglion cell layer (GCC) , focal loss of volume (FLV), global loss of volume (GLV), peripapillary, papillary vessel density (VD), ocular axial length (AL) and intraocular pressure (IOP).
Among functional tests there were significant differences in contrast sensitivity at 1.5 ( < 0.001), 6 ( < 0.013), 12 (p < 0.001), 18 ( < 0.003) cycles per degree, in near stereoacuity (Titmus Wirt circles, < 0.001) and in best corrected visual acuity (BCVA, p < 0.001). A statistically significant, moderate positive linear correlation was observed between BCVA and average Phe levels over the last ten years (β = 0.49, < 0.001). The average (p < 0.001), superior (p < 0.001) inferior GCC (p < 0.001), the FLV ( < 0.003), GLV (p < 0.001) and the average RNFLT ( < 0.004) values of the PKU group were significantly lower than the controls. The serum phenylalanine level (Phe) in the PKU group negatively correlated with inferior (-0.32, < 0.007), and average (-0.29 < 0.014) RNFL and with AL (-0.32, < 0.026). In AL we detected a significant difference ( < 0.04) between the good and suboptimal dietary controlled group. There was no significant difference between the ETPKU and control group in the measured vessel density parameters and in IOP.
Our results suggest that functional and ocular microstructural defects are present in patients with PKU, and some of them may depend on dietary control. The mechanism is unclear, but the correlation indicates the importance of strict dietary control in terms of preservation of retinal functions.
在早期治疗的苯丙酮尿症（ETPKU）中，视网膜变化的描述较少。我们旨在研究成年ETPKU患者可能存在的视觉功能和眼部微观结构变化。将苯丙酮尿症患者的光学相干断层扫描（OCT）及其血管造影（OCTA）数据与健康对照进行比较。
在这项前瞻性、单中心、横断面病例对照研究中，对50例ETPKU患者和50名健康受试者进行了OCT和OCTA评估。测量在右眼进行。研究了以下视觉功能参数：最佳矫正视力（BCVA）、等效球镜度（SE）、对比敏感度和近立体视锐度；微观结构参数：视网膜神经纤维层厚度（RNFLT）、神经节细胞层（GCC）、局部体积损失（FLV）、整体体积损失（GLV）、视乳头周围、视乳头血管密度（VD）、眼轴长度（AL）和眼压（IOP）。
在功能测试中，每度1.5（<0.001）、6（<0.013）、12（p<0.001）、18（<0.003）周期的对比敏感度、近立体视锐度（Titmus Wirt圆圈，<0.001）和最佳矫正视力（BCVA，p<0.001）存在显著差异。观察到BCVA与过去十年的平均苯丙氨酸水平之间存在统计学上显著的中度正线性相关性（β=0.49，<0.001）。PKU组的平均（p<0.001）、上方（p<0.001）、下方GCC（p<0.001）、FLV（<0.003）、GLV（p<0.001）和平均RNFLT（<0.004）值显著低于对照组。PKU组的血清苯丙氨酸水平（Phe）与下方（-0.32，<0.007）、平均（-0.29，<0.014）RNFL以及与AL（-0.32，<0.026）呈负相关。在AL方面，我们检测到饮食控制良好组和欠佳组之间存在显著差异（<0.04）。ETPKU组和对照组在测量的血管密度参数和眼压方面没有显著差异。
我们的结果表明，PKU患者存在功能和眼部微观结构缺陷，其中一些可能取决于饮食控制。机制尚不清楚，但这种相关性表明严格饮食控制在保护视网膜功能方面的重要性。
