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Monozygotic twins (aged 63 years old), with group‐2A idiopathic juxtafoveolar retinal telangiectasia (JXT), underwent clinical examination, fluorescein angiography (FA) and optical coherence tomography (OCT). Twin 1: Right fundus showed right‐angled venules temporal to the fovea; FA demonstrated retino‐retinal anastomosis and intraretinal leakage. Twin 2: Fundoscopy revealed right‐angled venules in both eyes. OCT demonstrated foveal cysts in all eyes. This is the third set of monozygotic twins with group‐2A JXT that has been reported in the literature, further supporting a genetic predisposition for JXT. The twin who smoked had more severe disease, suggesting that smoking is a risk factor for progression. OCT is useful in the detection and monitoring of these patients.
Group‐2A JXT is characterised by bilateral regions of retinal thickening temporal to the fovea with minimal exudation.1 Gass and Blodi described five stages of group‐2A JXT.1 OCT clearly depicts the involvement of the intraretinal and subretinal spaces in this condition. Intraretinal cysts, lamellar hole, subretinal fibrosis and speckled intraretinal yellow‐red hyper‐reflectivity have been reported.2
We report identical twin sisters with group‐2A JXT.
A 63‐year‐old woman, a smoker, presented with 4 months' history of right metamorphopsia. She was diagnosed with subretinal neovascularisation (SRNVM) in the left eye 7 years previously. The corrected visual acuities were 20/50 OD and 20/30 OS. Right fundoscopy revealed dilated right‐angled venules and loss of retinal transparency supero‐temporal to the fovea (fig 1A1A).). The left eye showed juxtafoveal hyperpigmented scars (fig 1B1B).). Fluorescein angiography (FA) in the early phase showed right‐angled venules leading to a network of proliferating vessels in the deeper retina, forming a retinal‐retinal anastomosis in the right eye (fig 1C1C)) and the late phase showed perifoveolar retinal leakage (fig 1D1D).). OCT showed a non‐reflective space at the fovea in both eyes (fig 2A, 2B2B).
The identical twin sister of the first patient, a non‐smoker, presented with transient metamorphopsia in the left eye. The corrected visual acuities were 20/30 in both eyes. Fundoscopy showed typical right‐angled vessels and crystalline yellow macular deposits. OCT demonstrated lamellar cysts at the fovea in both eyes (fig 2C, 2D2D).
Menchini et al. reported monozygotic twins with JXT with identical fluorescein patterns.3 The identical twins with JXT, as reported by Siddiqui et al., had a similar non‐proliferative stage of the disease, with different fluorescein patterns.4 We report the third set of monozygotic twins with group‐2A JXT, one who is a smoker with stage 5 proliferative changes and the other who is a non‐smoker with stage 3 disease. Frank Holz used fundus autofluorescence imaging to record the macular pigment density and distribution in JXT.5 He found significant depletion of luteal pigment in the macular area, with a well‐defined ring‐shaped increase at the peripheral margin in group‐2A JXT. He suggests that primary dysfunction of retinal pigment epithelium (RPE), glial or Mueller cells leads to abnormal transport of macular pigments, lutein and zeaxanthin. The vascular alterations occur as a secondary phenomenon.5 This may explain why the twin who is a smoker has a more advanced stage of the disease, with development of SRNVM. The addition of our report to the literature strengthens the implications for a genetic predisposition to this condition. Advice against smoking should be given to those who have the condition, as well as to other members of the family.
OCT showed inner lamellar cysts with normal retinal thickness. The high‐intensity RPE signal was uniform in appearance except in the left eye of twin 1, who had a previous SRNVM.
OCT constitutes a quick and non‐invasive diagnostic tool in monitoring the progressive loss of the outer retina as well as the advent of SRNVM in these patients.
Competing interests: None.