P1‐123: VERY YOUNG ONSET AUTOSOMAL DOMINANT ALZHEIMER'S DISEASE WITH SPASTIC PARAPARESIS DUE TO A NOVEL (F388S) PSEN1 MUTATION. (1st July 2019) - Ringman, John M.; Dorrani, Naghmeh; Signer, Rebecca; Martinez-Agosto, Julian; Lee, Hane; Douine, Emilie; Qiao, Yuchuan; Wang, Junyan; Shi, Yonggang; D'Orazio, Lina; Cederbaum, Stephan; Nelson, Stanley; et al.