Multisystem inflammatory syndrome in children (MIS-C) is a rare and severe condition that
follows benign COVID-19. We report autosomal recessive deficiencies of OAS1, OAS2, or
RNASEL in five unrelated children with MIS-C. The cytosolic double-stranded RNA (dsRNA)–
sensing OAS1 and OAS2 generate 2′-5′-linked oligoadenylates (2-5A) that activate the
single-stranded RNA–degrading ribonuclease L (RNase L). Monocytic cell lines and primary
myeloid cells with OAS1, OAS2, or RNase L deficiencies produce excessive amounts of …

… Although some children have had severe coronavirus 2019 (COVID) pneumonia and
acute illness, it was discovered in 2020 that some present around four weeks after infection
with an inflammatory illness having some similarity to Kawasaki disease. This condition was
named multisystem inflammatory disease in children (MIS-C) and affects 1 in 10 000
children infected with severe acute respiratory syndrome coronavirus 2. Much has been
learned about MIS-C over the past few years and this study is a genetic evaluation of a …