Blood antigen group (Vyas et al., 2020); serology that is indicative of prior GAS infection (anti-SLO or anti-DNase B antibodies); ethnicity; chronic liver disease; long-term alcohol abuse; homelessness, household crowding or relevant socioeconomic condition (Siemens and Lütticken, 2021); scabies as risk factor for pyoderma; immunity-suppressing pharmaceuticals; human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS); family history of GAS-related disease; and twin status (monozygotic or dizygotic). The gene discussed is KCNMA1; the disease is AIDS.