The specificity of VHH‐B9 for BACE1 also avoids issues of impaired glucose homeostasis, hypopigmentation, seizures, and blindness (among others), which are associated with cross‐reactivity with BACE2, Cathepsin D, and Cathepsin E (Voytyuk et al, 2018). The gene discussed is CTSE; the disease is Blindness.