Two knockout genes interacted with the GWAS AMD genes: sortilin-related receptor 1 (SORL1), a gene coding for a receptor involved in intracellular sorting of protein which is primarily associated with Alzheimer disease,20 and tyrosine aminotransferase (TAT), which is involved in the tyrosine breakdown pathway (Fig. 3C). This evidence concerns the gene TAT and early-onset autosomal dominant Alzheimer disease.