TFRC and early-onset autosomal dominant Alzheimer disease: Together, they have provided new optimism on how to achieve delivery of therapeutics to the brain, with transferrin receptor-targeted antibodies being now amendable for clinical use in conjugation with enzymes needed for treatment of lysosomal deficiency or being tested in clinical trials against amyloid deposition in Alzheimer’s disease (ClinicalTrials.gov Identifier: NCT05371613; NCT04639050; NCT04573023).