Optic atrophy due to Moya Moya disease in Trisomy 21

<h3></h3> A 38-year-old woman with trisomy 21 presented with unilateral optic nerve atrophy due to Moyamoya Disease (MMD). She had a narrow palate, epicanthal folds and moderate developmental delay. Her past ocular history was normal. Her mother noted a change in visual behavior. Neuro-ophthalmic examination showed a visual acuity of 20/80 OD and 20/25 OS and a relative afferent pupillary defect OD. The patient could not perform automated perimetry. Slit lamp biomicroscopy showed Brushfield spots OU. Ophthalmoscopy showed diffuse optic atrophy OD and a normal optic nerve OS. Testing including serum B12 and B9 levels, syphilis serology, tuberculosis IGRA, and chest radiography were negative. MRI with contrast showed chronic lacunar infarcts in the periventricular white matter and absence of the left internal carotid artery (ICA) flow void likely due to occlusion. The right optic nerve was atrophic with increased T2 signal. CTA with contrast showed chronic occlusion of the left ICA, right posterior cerebral artery, right middle cerebral artery and left anterior cerebral artery A2 segment with extensive collateralization. Severe narrowing of the proximal left ICA beginning 5 mm beyond the bifurcation was noted. A catheter cerebral angiogram confirmed MMD. Vascular neurology and neurosurgery were consulted. Aspirin 81 mg daily was started. Moyamoya angiopathy is rare, optic atrophy is an unconventional presentation and they can be associated with trisomy 21. Studies are warranted to better understand and treat this condition.