ABSTRACT

Background

Choroideremia is an X-linked chorioretinal dystrophy caused by mutations in the CHM gene. The main differential diagnosis is X-linked retinitis pigmentosa. Clinically, male patients that are affected by these two diseases have similar symptoms. This work aims to report a familial case of choroideremia initially diagnosed as X-linked retinitis pigmentosa with a novel mutation in the CHM gene, and the relevance of fundus autofluorescence (FAF) in female carriers.

Materials and Methods

A complete ophthalmological evaluation was done in a 37-year-old woman and her 53-year-old maternal uncle; the uncle had been diagnosed previously with X-linked retinitis pigmentosa. A visual field test, FAF imaging, full-field electroretinography, and a genetic test were performed.

Results

In the proband, the fundoscopy revealed diffuse changes in the retinal pigment epithelium in both eyes, and the FAF showed a speckled pattern of low- and high-density. The maternal uncle’s ophthalmological evaluation showed choroidal and retinal atrophy consistent with choroideremia. The molecular analysis revealed a pathogenic variant in the CHM gene, c.190–1 G > T.

Conclusions

In female carriers of choroideremia and X-linked retinitis pigmentosa, differential diagnosis may be challenging. A speckled pattern of low- and high-density in autofluorescence is commonly found in female carriers of choroideremia. FAF is a powerful tool for making a correct clinical diagnosis because the pattern in FAF is much more apparent than the visible retinal changes obtained by fundoscopy. Although it is crucial to perform molecular analysis to confirm the diagnosis, FAF is useful when genetic testing may not be readily available.

中文翻译：

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患有脉络膜炎的女性携带者中的自体荧光：家族性病例，CHM基因发生新突变。

摘要

背景

脉络膜炎是由CHM基因突变引起的X连锁脉络膜视网膜营养不良。主要的鉴别诊断是X连锁性视网膜色素变性。在临床上，受这两种疾病影响的男性患者具有相似的症状。这项工作旨在报告最初诊断为X连锁性色素性视网膜色素变性视网膜炎的家族性病例，其CHM基因发生新突变，以及女性携带者眼底自发荧光（FAF）的相关性。

材料和方法

对一名37岁妇女和她53岁的产妇叔叔进行了完整的眼科评估；叔叔先前曾被诊断出患有X连锁性视网膜色素变性。进行了视野测试，FAF成像，全场视网膜电图和基因测试。

结果

在先证者中，眼底镜检查显示两只眼睛的视网膜色素上皮弥漫性变化，FAF显示出低密度和高密度的斑点图案。产妇叔叔的眼科评估显示脉络膜和视网膜萎缩与脉络膜增生症一致。分子分析揭示了CHM基因的致病变异，c.190–1 G>T。

结论

在女性脉络膜炎和X连锁性视网膜色素变性患者中，鉴别诊断可能具有挑战性。通常在女性脉络膜炎携带者中发现低密度和高密度的自发荧光斑点图案。FAF是进行正确临床诊断的有力工具，因为FAF中的模式比通过眼底镜检查获得的可见视网膜变化要明显得多。尽管进行分子分析以确认诊断至关重要，但是当基因检测可能不容易进行时，FAF很有用。