Another example is autoimmune lymphoproliferative syndrome (ALPS-FAS), where homozygous or CH mutations in the FAS gene are fully penetrant and present early-onset, while AD mutations are less penetrant with a hierarchy according to the location of the mutation (higher penetrance in the intracellular domain compared to the extracellular domain). The gene discussed is FAS; the disease is autoimmune lymphoproliferative syndrome.