Background:Myocardial infarction (MI) is a type of severe coronary artery disease (CAD) that can lead to heart failure and sudden cardiac death. The prevalence of heart failure globally is estimated at 1%–2%, of which ∼60% of cases are the consequence of MI as the primary cause. At present, several disease-causing genes have been identified that may be responsible for MI, such as autophagy-related 16-like 1 (ATG16L1) and RecQ-like helicase 5 (RECQL5).Methods:In this study, we enrolled a Chinese family with MI, CAD, and stroke hemiplegia. Whole-exome sequencing was applied to analyze the genetic lesion of the proband. Sanger sequencing was used to validate the candidate mutation in five family members and 200 local control cohorts.Results:After data filtering, we detected a novel mutation (NM_004259: c.1247T>C/p.I416T) of RECQL5 in the proband. Sanger sequencing further validated that the novel mutation was existent in the affected individuals, including the proband’s younger sister and her mother, and absent in the other healthy family members and 200 local control cohorts. Furthermore, bioinformatics analysis confirmed that the novel mutation, located in a highly evolutionarily conserved site, was predicted to be deleterious and may change the hydrophobic surface area and aliphatic index of RECQL5.Conclusion:Here, we report the second mutation (NM_004259: c.1247T>C/p.I416T) of RECQL5 underlying MI and CAD by whole-exome sequencing. Our study expanded the spectrum of RECQL5 mutations and contributed to genetic diagnosis and counseling of MI and CAD.