AR LOF mutations in OAS1 were recently shown to cause the multisystem inflammatory syndrome in children (Lee et al., 2022); and heterozygous OAS1 gain-of-function (GOF) variants cause a polymorphic autoinflammatory immunodeficiency (OPAID), characterized by recurrent fever, dermatitis, inflammatory bowel disease, pulmonary alveolar proteinosis, and hypogammaglobulinemia (Cho et al., 2018; Magg et al., 2021). The gene discussed is OAS1; the disease is pulmonary alveolar proteinosis.