CD27 and Alzheimer disease: CID may present as an isolated immune disorder (e.g., CD40 Ligand deficiency, Bare Lymphocyte Syndrome, CD27-CD70 deficiency, DOCK 8 deficiency) or as immune disorders with associated or syndromic features (e.g., Wiskott Aldrich syndrome (WAS), autosomal dominant anhidrotic ectodermal dysplasia with immune deficiency (AD EDA-ID) [3, 8, 67–69].