Taking into account the nature of mutations in the complement system and the highly complex effects that result, the number of pathologies associated with complement defects (and components of the innate immune system for that matter; see TLR7 [86], PKR [87,88] and PACT [89]) will continually evolve, but to date, other than those listed above, this includes Alzheimer’s, diabetes mellitus, rheumatoid arthritis (RA), systemic scleroderma (SS), and cancer. The gene discussed is EIF2AK2; the disease is rheumatoid arthritis.