Li Yujing, Ding Yihong, Jin Enzhong, Yin Hong
Department of Ophthalmology, Peking University People's Hospital, Beijing, China.
Beijing Key Laboratory of Ocular Disease and Optometry Science, Peking University People's Hospital, Beijing, China.
Front Pediatr. 2025 Aug 21;13:1573886. doi: 10.3389/fped.2025.1573886. eCollection 2025.
The m.3243A>G mutation in the MT-TL1 gene is the most common mtDNA mutation. The mutation can lead to a spectrum of conditions, including diabetes, hearing loss, heart and muscle involvement, encephalopathy and epilepsy, gastrointestinal problems, and vision impairment, often occurring concurrently-collectively referred to as MELAS (mitochondrial encephalopathy lactic acidosis and stroke-like episodes) syndrome. Currently, it has been reported that the ocular manifestations of m.3243A>G include posterior subcapsular cataract, ptosis, extraocular muscle paralysis, and retinitis pigmentosa, among which retinitis pigmentosa is the most common ocular manifestation.
The ocular manifestations of a 10-month-old infant with mitochondrial MT-TL1 gene m.3243A>G mutation detected by genetic testing due to developmental delay were reported.
Ocular examination revealed Schiotz tonometry conversion values of 5.5/6 in the right eye (OD) and 5.5/4 in the left eye (OS) for intraocular pressure. Cycloplegic refraction measured +9.50 DS/-2.00 DC × 110° (OD) and +4.00 DS/-1.75 DC × 30° (OS). Anterior segment evaluation showed an irregular vertically oval pupil with absence of the temporal iris OD and a fusiform pupil OS, with no other anterior segment abnormalities detected in either eye. Fundus examination demonstrated clear optic disc boundaries bilaterally and a cup-to-disc (C/D) ratio of 0.3. Sodium fluorescein angiography revealed an intact retina without evidence of peripheral vascular leakage.
Iris defect in a infant caused by m.3243A>G mutation was reported, which complements the ocular signs of this mutation and provides a new aspect for eye screening.
MT-TL1基因中的m.3243A>G突变是最常见的线粒体DNA突变。该突变可导致一系列病症，包括糖尿病、听力丧失、心脏和肌肉受累、脑病和癫痫、胃肠道问题以及视力障碍，这些病症常同时出现，统称为MELAS（线粒体脑病乳酸酸中毒和卒中样发作）综合征。目前，已有报道称m.3243A>G的眼部表现包括后囊下白内障、上睑下垂、眼外肌麻痹和色素性视网膜炎，其中色素性视网膜炎是最常见的眼部表现。
报告一名因发育迟缓经基因检测发现线粒体MT-TL1基因m.3243A>G突变的10个月大婴儿的眼部表现。
眼部检查显示右眼（OD）眼压的Schiotz眼压计换算值为5.5/6，左眼（OS）为5.5/4。睫状肌麻痹验光结果为右眼+9.50 DS/-2.00 DC×110°，左眼+4.00 DS/-1.75 DC×30°。前段评估显示右眼颞侧虹膜缺失，瞳孔呈不规则垂直椭圆形，左眼瞳孔呈梭形，双眼均未检测到其他前段异常。眼底检查显示双侧视盘边界清晰，杯盘比（C/D）为0.3。荧光素钠血管造影显示视网膜完整，无周边血管渗漏迹象。
报道了由m.3243A>G突变引起的婴儿虹膜缺损，补充了该突变的眼部体征，为眼部筛查提供了新的视角。
