A number of studies have been conducted with the onset of secondary progressive multiple sclerosis as an inclusion criterion or an outcome of interest. However, a standardized objective definition of secondary progressive multiple sclerosis has been lacking. The aim of this work was to evaluate the accuracy and feasibility of an objective definition for secondary progressive multiple sclerosis, to enable comparability of future research studies. Using MSBase, a large, prospectively acquired, global cohort study, we analysed the accuracy of 576 data-derived onset definitions for secondary progressive multiple sclerosis and first compared these to a consensus opinion of three neurologists. All definitions were then evaluated against 5-year disease outcomes post-assignment of secondary progressive multiple sclerosis: sustained disability, subsequent sustained progression, positive disability trajectory, and accumulation of severe disability. The five best performing definitions were further investigated for their timeliness and overall disability burden. A total of 17 356 patients were analysed. The best definition included a 3-strata progression magnitude in the absence of a relapse, confirmed after 3 months within the leading Functional System and required an Expanded Disability Status Scale step ≥4 and pyramidal score ≥2. It reached an accuracy of 87% compared to the consensus diagnosis. Seventy-eight per cent of the identified patients showed a positive disability trajectory and 70% reached significant disability after 5 years. The time until half of all patients were diagnosed was 32.6 years (95% confidence interval 32-33.6) after disease onset compared with the physicians' diagnosis at 36 (35-39) years. The identified patients experienced a greater disease burden [median annualized area under the disability-time curve 4.7 (quartiles 3.6, 6.0)] versus non-progressive patients [1.8 (1.2, 1.9)]. This objective definition of secondary progressive multiple sclerosis based on the Expanded Disability Status Scale and information about preceding relapses provides a tool for a reproducible, accurate and timely diagnosis that requires a very short confirmation period. If applied broadly, the definition has the potential to strengthen the design and improve comparability of clinical trials and observational studies in secondary progressive multiple sclerosis.

Cerebroretinal vasculopathy, hereditary vascular retinopathy, and hereditary endotheliopathy, retinopathy, nephropathy and stroke are neurovascular syndromes initially described as distinct entities. Recently they were shown to be one disease caused by C-terminal frame-shift mutations in TREX1, which was termed 'retinal vasculopathy with cerebral leukodystrophy'. Here we defined the genetic and clinicopathologic spectrum of this clinically and pathophysiologically poorly characterized and frequently misdiagnosed fatal neurovascular disorder. We identified five different TREX1 mutations in 78 members from 11 unrelated families and by using a standardized study protocol we retrospectively reviewed and aggregated the associated clinical, neuroimaging, and pathology data. Findings were similar across mutations and families. Sixty-four mutation carriers had vascular retinopathy. Neuroimaging revealed (i) punctate, hyperintense, white matter lesions with or without nodular enhancement in 97% of them; (ii) rim-enhancing mass lesions in 84%; and (iii) calcifications in the white matter in 52%. Ninety per cent had clinical manifestations of brain disease, including focal neurological deficits (68%), migraine (59%), cognitive impairment (56%), psychiatric disturbances (42%), and seizures (17%). One mutation carrier had enhancing brain lesions and neurological features but unknown retinopathy status. Additional systemic features included liver disease (78%), anaemia (74%), nephropathy (61%), hypertension (60%), mild Raynaud's phenomenon (40%), and gastro-intestinal bleeding (27%). Mean (AE standard deviation) age at diagnosis was 42.9 AE 8.3 years and at death 53.1 AE 9.6 years. Pathological examination revealed systemic vasculopathy with luminal narrowing and multi-laminated basement membranes. The 13 mutation carriers without retinopathy or brain lesions were on average 8 years younger (mean age: 35.1 AE 10.6 years). Of them, 54% had mild Raynaud's phenomenon, 42% had migraine, and 23% had psychiatric disturbances. Retinal vasculopathy with cerebral leukodystrophy is an autosomal dominant systemic small-vessel disease due to specific TREX1 mutations and clinically primarily characterized by (i) visual impairment from vascular retinopathy; and (ii) neurological decline and premature death due to progressive enhancing cerebral white matter lesions. Impaired liver and kidney function, anaemia sometimes associated with gastrointestinal bleeding, hypertension, migraine, and Raynaud's phenomenon appear to be part of the clinical spectrum as well. Penetrance

We provide evidence of long-term treatment benefit in a large registry cohort, and provide evidence of long-term protective effects of pregnancy against disability accrual. We demonstrate that high annualized relapse rate, particularly on-treatment relapse, is an indicator of poor prognosis. Ann Neurol 2016;80:89-100.

National Health and Medical Research Council, and the University of Melbourne.

ObjectivesWe have undertaken a clinic-based survey of neuromyelitis optica spectrum disorders (NMOSD) in Australia and New Zealand in order to establish incidence and prevalence across the region and in populations of differing ancestry.Background NMOSD is a recently defined demyelinating disease of the central nervous system. The incidence and prevalence of NMOSD in Australia and New Zealand has not been established. European ancestry. We found NMOSD to be more common in the population with Asian ancestry. Methods