PReS-FINAL-2125: A Japanese girl with childhood-onset anti-Ku antibody positive generalized morphea-myositis overlap syndrome

Methods We retrospectively explore the difference between childhood anti-Ku positive syndromes, juvenile dermatomyositis and adult onset anti-Ku positive syndromes. Results The patient, a 16-year-old Japanese girl, first developed symptoms at the age of 7. Her initial symptoms consisted of multiple brownish plaques on her left forearm that gradually extended to her upper arm, back, and left thigh. She underwent a skin biopsy at the age of 8 that revealed generalized morphea(GM). Laboratory findings included positive anti-nuclear antibody (1:1,280) and elevated serum creatine kinase (CK, 1,249 U/L) even though she lacked clinical evidence of myositis, myocardial failure or muscular dystrophy. Repeated skin biopsy at the age of 14 revealed lymphocytic infiltrations around vessels and thickened collagen bundles in the dermis. Although she still lacked clinical signs of muscular involvement, MRI demonstrated findings consistent with myositis and bilateral thigh atrophy. Furthermore, serum anti-Ku antibody