IDS and Alzheimer disease: Significant advances were made with anti-TfR1 antibodies as brain shuttles for delivering of iduronate-2-sulfatase (IDS) for mucopolysaccharidosis type II (MPSII), anti-amyloid beta antibody (gantenerumab) for AD and progranulin for frontotemporal dementia, with clinical trials ongoing [6,7,8,9].