Supplementary Material for: Familial Exudative Vitreoretinopathy Initially Diagnosed as Incontinentia Pigmenti in an Asymptomatic Teenager

In this case report, we aim to illustrate a presentation of familial exudative vitreoretinopathy (FEVR) that closely resembles incontinentia pigmenti (IP) and the role of genetic testing that is of no cost to the patient in providing the correct diagnosis. We present a case of an 11-year-old female-to-male (FTM) transgender patient with a history of hypodontia and skin hypopigmentation was incidentally found to have a retinal lesion on ultra-widefield fundus imaging during routine screening. Ultra-widefield fluorescein angiography confirmed bilateral peripheral ischemic retinopathy that was successfully treated with laser. The patient was presumed to have IP, however genetic testing was negative. Due to cost, further genetic testing was declined by family and the patient had no further ocular complaints. At age 16, genetic testing became available to the patient, and the patient was found to have FEVR with LRP5 mutation. The patient began screening for comorbidities associated with LRP5 mutation. This case highlights how the ophthalmologic findings of FEVR can present identically to those of IP, and genetic testing is an invaluable tool in distinguishing between these two pathologies. Correct diagnosis of FEVR is vital in assessing for other comorbidities of the disease, including osteoporosis. Furthermore, increased use of ultra-widefield fundus imaging in routine eye screening may be of great benefit for community screening of retinal disease, and ultra-widefield fluorescein angiography is of significant use in the diagnosis of FEVR.