Cilioretinal-Sparing Central Retinal Artery Occlusion in a Child with Adenosine Deaminase 2 (ADA2) Deficiency.

PURPOSE: To report cilioretinal-sparing central retinal artery occlusion (CRAO) in a child with adenosine deaminase 2 (ADA2) deficiency and polyarteritis nodosa-like systemic vasculitis. METHODS: This retrospective case report was based on clinical records, retinal imaging, automated visual field testing, systemic evaluation, and genetic testing. RESULTS: An 11-year-old girl first presented with intermittent exotropia and a normal fundus. Eight months later, she developed fever, weight loss, post-prandial abdominal pain, vasculitic rash, and hypertensive urgency. Her elder brother was also diagnosed with severe hypertension. Skin biopsy revealed medium-vessel vasculitis, raising suspicion for monogenic polyarteritis nodosa-like vasculitis. ADA2 testing was initiated, and she began treatment with oral prednisolone and azathioprine. Twelve months after her initial ophthalmic visit, she maintained best-corrected visual acuity of 20/20 in both eyes but showed a neuroretinitis-like appearance in the left eye, including subtle optic disc margin blurring, sectoral retinal whitening, perivascular sheathing, and peripapillary exudation. One week later, she reported a grey central field disturbance. Visual acuity remained 20/20, but automated perimetry revealed a dense paracentral scotoma. At this time, genetic testing confirmed a homozygous pathogenic ADA2 variant in both siblings. Fundus examination and optical coherence tomography identified CRAO with cilioretinal artery territory sparing. She was treated with intravenous methylprednisolone, blood pressure management, and adalimumab. At 6 months, visual acuity remained stable, with persistent paracentral field loss and structural sequelae of CRAO. CONCLUSION: ADA2 deficiency should be considered in children with retinal arterial occlusion, especially when systemic vasculitis, severe hypertension, or sibling involvement is present.