Bks is required for Tll function, and so is Atrophin [21], the homolog of human Atrophin-1, which causes the neurodegenerative disease dentatorubral-pallidoluysian atrophy (DRPLA) when a polyglutamine stretch in the protein is expanded (reviewed in [22]). The gene discussed is NR2E1; the disease is Dentatorubral pallidoluysian atrophy.