BACKGROUND: Despite efforts by the National Education on Sleeping Environment to reduce sudden infant death syndrome (SIDS), it remains the leading cause of post-neonatal mortality. In Korea, the incidence of SIDS was estimated at 0.4 per 1,000 infants in 2022. Mutations in the ryanodine receptor 2 ( METHODS: We extracted DNA from archived formalin-fixed, paraffin-embedded myocardial tissues from 249 SIDS cases autopsied between 2005 and 2017. DNA analysis focused on sequencing key exons (3, 8, 14, 15, 37, 42, 44-47, 49, 50, 83, 87-91, 93-95, 97, 99, and 100-105) of the RESULTS: Among the 249 SIDS cases, 62% were male infants, with an average age of 124 days, all of Asian-Korean descent. We identified two previously unreported CONCLUSION: Our study identified two