Background/Objectives: Thoracic aortic aneurysms (TAA) represent medical conditions having causes that can range from genetic determinations to various risk factors, having potential life-threatening complications, the familial TAA (FTAA) being a cluster of non-syndromic thoracic aortic aneurysms. This review aims to emphasize the importance of genetic testing in patients diagnosed with thoracic aortic aneurysms, the genetic implications accounting for roughly 20% of these cases. The reported case presents a patient who was genetically tested 10 years after a Bentall procedure, which was performed for acute DeBakey type I aortic dissection developed in her second pregnancy, when the patient started presenting recurrent prolonged febrile syndrome. She was tested positive for a missense variant in the actin alpha-2 (ACTA2) gene, in heterozygous status, but also serological tests revealed the presence of an infection with Coxiella burnetii. Methods: For a better understanding of both conditions, our research was conducted on two directions, one reviewing the literature on patients with Coxiella burnetii blood culture-negative infective endocarditis (BCNIE) and the other one, focusing on patients having familial thoracic aortic aneurysm (FTAA) due to ACTA2 mutation. This review incorporates studies found on PubMed and ResearchGate up to August 2024. Conclusions: BCNIE represents a condition with several diagnosis challenges and may lead to severe complications if timely treatment is not initiated. Also, diagnosing FTAA requires more frequent genetic testing, enabling a better follow-up and management.