Introduction: Acute myocardial infarction (AMI) is a specific type of coronary artery disease (CAD) caused by the rupture of coronary atherosclerotic plaques. Coronary artery ectasia (CAE) is a rare phenotype of cardiovascular disease that may promote thrombosis and inflammatory responses leading to myocardial infarction due to abnormal dilatation of blood vessels and coronary blood flow disorders. It is a complicated disease and shows interaction between genetic and environmental factors. Patient concerns: A 34-year-old male patient was admitted to our hospital on May 12, 2016, with complaints of chest pain for 1 hour duration. Diagnosis: Coronary angiography through the emergency medical service (EMS) system showed 100% occlusion at the first turning point of the right coronary artery (RCA), along with tumor-like expansion of the proximal segment of the RCA and the end of the left main (LM) artery. The patient was diagnosed with AMI and CAE. Three-point mutations in the ATG16L1 gene were identified by direct sequencing. Interventions: After admission, the patient underwent emergency green channel coronary angiography and percutaneous coronary intervention (PCI) to assess and unblock the stenosis and occlusion of the RCA lumen, but no stenting was performed because the catheter could not pass the second inflection point of the RCA. Aspirin enteric-coated tablets, clopidogrel sulfate tablets, tirofiban hydrochloride, and low molecular weight heparin calcium were given as anticoagulant and antiplatelet therapy. Atorvastatin calcium tablets were used to regulate blood lipid levels. Perindopril and spironolactone were used to inhibit the renin-angiotensin-aldosterone system (RAAS) to reverse myocardial remodeling. Acetylcholinesterase inhibitors (ACEI) and beta blockers were administered to resist ventricular remodeling and improve cardiac function and prognosis after the patient's blood pressure and heart rhythm were stabilized. Outcomes: After active rescue treatment, the patient recovered and was discharged. A coronary angiogram performed 2 years later showed that the RCA blood flow was restored, and the patient had recovered well. Conclusion: Three-point mutations in the ATG16L1 gene were identified in a patient with AMI and CAE, which extended the mutation spectrum of the ATG16L1 gene. Hence, the etiology of coronary artery aneurysmal dilatation is worthy of further investigation.

BackgroundAcute myocardial infarction (AMI), a common complex disease caused by an interaction between genetic and environmental factors, is a serious type of coronary artery disease and is also a leading cause of death worldwide. Autophagy-related 16-like 1 (ATG16L1) is a key regulatory factor of autophagy and plays an important role in induced autophagy. In the cardiovascular system, autophagy is essential to preserve the homeostasis and function of the heart and blood vessels. No studies have hitherto examined the association between AMI and ATG16L1 gene promoter.MethodsWe conducted a case-control study, using polymerase chain reaction and sequencing techniques, dual luciferase reporter assay, and electrophoretic mobility shift assay, to analyze genetic and functional variation in the ATG16L1 gene promoter between AMI and controls. A variety of statistical analyses were used to analyze the allele and genotype frequencies and the relationship between single-nucleotide polymorphisms (SNPs) and AMI.ResultsIn all, 10 SNPs and two DNA-sequence variants (DSVs) were identified in 688 subjects, and three ATG16L1 gene promoter mutations [g.233250693 T > C (rs185213911), g.233250946 G > A (rs568956599), g.233251133 C > G (rs1301744254)] that were identified in AMI patients significantly altered the transcriptional activity of ATG16L1 gene promoter in HEH2, HEK-293, and H9c2 cells (P < 0.05). Further electrophoretic mobility shift assays indicated that the SNPs affected the binding of transcription factors (P < 0.01).ConclusionATG16L1 gene promoter mutations in AMI patients may affect the binding of transcription factors and change the transcriptional activity of the ATG16L1 gene, changing the level of autophagy and contributing to the occurrence and development of AMI as rare and low-frequency risk factors.