IMPG1 Variant Causing Adult-Onset Foveomacular Vitelliform Dystrophy in Chinese: A Case Report

Adult-onset foveomacular vitelliform dystrophy (AOFVD) is a rare entity and is mostly reported in French individuals. Here, we report a Chinese patient with AOFVD who had IMPG1 mutation and was misdiagnosed with age-related macular degeneration (AMD).

A 59-year-old man complaining of vision loss was misdiagnosed with AMD and treated with intravitreal injections of anti-vascular endothelial growth factor, but with no improvement. Visual acuity was 20/50 in the right eye and 20/40 in the left eye. Fundus examinations revealed a bilateral symmetrical vitelliform "egg yolk" lesion. Spectral-domain optical coherence tomography revealed dome-shaped subretinal hyperreflective materials and cuticular drusen at the retinal pigment epithelium-Bruch's membrane complex in both eyes. No clear neovascularization was observed. Electrooculography revealed a decreased Arden ratio. Based on multimodal imaging analysis and genetic testing, the patient was diagnosed with AOFVD. No therapeutic intervention was administered. One month after the patient's visit, vitelliform "egg yolk" lesion was absorbed in the right eye, and the patient's visual acuity decreased to 20/100 in the right eye.

AOFVD is rare and underdiagnosed. It can disguise as AMD or other similar macular diseases. Clinicians should be alert to this condition, pay attention to its identification, and avoid unnecessary treatments.