Inflammatory Optic Neuropathy as a Presenting Feature of Cerebral Autosomal Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy.

Background: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is commonly associated with early-onset stroke, migraine and vascular dementia. However, optic nerve involvement has been previously recognised. Results: We report a case of a 21-year-old female presenting with right inferior temporal scotoma, dyschromatopsia, relative pupillary afferent defect and bilateral disk oedema in the fundoscopic examination. Visual evoked potential latencies were bilaterally increased, suggesting optic neuropathy. Cerebrospinal fluid (CSF) evaluation showed 11 leukocytes, .45 mg/dL proteins, elevated IgG (4.55 mg/dL) and 2 oligoclonal bands (OCB) restricted to the CSF. ESR was 17 mm/h and CRP 5 mg/dL. Anti-Aquaporin4 anti-MOG antibodies were negative. The MRI showed right optic nerve hyperintensity, enhancing after the administration of contrast product, and multiple FLAIR focal lesions present throughout the white matter, with a noticeable confluence in the anterior temporal horns. She improved after IV high-dose methylprednisolone. Because the lesions of the white matter were highly atypical for an inflammatory disease and highly suggestive of CADASIL genetic testing was requested. A heterozygous pathogenic variant c994C>T p (Arg332Cys) in the exon 6 of the NOTCH3 gene, compatible with the diagnosis of CADASIL was found. Conclusions: This case highlights isolated optic nerve involvement as a presenting feature of CADASIL, possibly reflecting an inflammatory process associated with this hereditary vasculopathy.