<p> Clinically Isolated Acute Transverse Myelitis in Children: </p><p>Early Predictors of Relapse and Disability. </p><p>Kumaran Deiva1*, Michael Absoud2*, Cheryl Hemingway3, Yaiza Hernandez2, Béatrice </p><p>Hussson4, Hélène Maurey1, Giorgios Niotakis3, Evangeline Wassmer5, Ming Lim2#, Marc </p><p>Tardieu1# on behalf of United Kingdom Childhood Inflammatory Demyelination (UK-CID ) </p><p>Study and French Kidbiosep Study.</p><p>Supplemental Data</p><p>Probable TM Definite TM p n= 28 (29%) n=67 (71%) Age, mean ± SD 9.7 ± 4.8 8.9 ±4.4 ns Male 18 (64) 34 (51) ns Relapse 3 (11) 13 (19) ns Severity factors 7 (25) 21 (31) ns Country  UK 16 (57) 33 (49) ns  France 12 (43) 34 (51) ns Table e1. Comparative study of probable TM and definite TM, ns not significant.</p><p>Isolated ATM Relapsing Monophasic Relapsing Vs at onset disease disease Monophasic N=95 N=16 (17%) N= 79 (83%) disease p values Clinical characteristics Infection before attack (%) 30 (32) 5 (31) 25 (32) ns Familial auto-immune disease (%) 11 (12) 3 (19) 8 (10) ns Familial history of MS (%) 1 (1) 0 (0) 1(1) ns Treatments Steroids treatment (%) 90 (95) 16 (100) 74 (94) ns Table e2. Clinical characteristics of children with isolated acute transverse myelitis (ATM) are similar in the relapsing and monophasic disease. ns not significant.</p><p>Poor outcome Good outcome Poor (ASIA < D or (Asia ≥ D or EDSS outcome EDSS≥4) < 4) vs good N= 28 (30) N= 67 (70) outcome p values Clinical characteristics Infection before attack (%) 10 (36) 20 (30) ns Familial auto-immune disease (%) 2 (7) 9 (13) ns Treatments Steroids treatment (%) 26 (93) 64 (96) ns Table e3. Clinical characteristics of children with isolated acute transverse myelitis are independent of the outcome. ASIA American Spinal Injury Association Impairment Scale; EDSS Extended Disability Status Scale; ns not significant</p>