In the second example, Bolognesi et al. exploited the ability to measure the sequence-function relationships of thousands of variants in parallel to understand the relationship between aggregation and toxicity focussing on the PRD of the TAR DNA-binding domain 43 (TDP-43), the aggregation of which is linked to ALS [83••]. The gene discussed is TARDBP; the disease is amyotrophic lateral sclerosis.