Evaluating the monogenic contribution and genotype-phenotype correlation in patients with isolated thoracic aortic aneurysm.

Thoracic aortic aneurysm with or without dissection (TAAD) can be broadly categorized as syndromic TAAD (sTAAD) and isolated TAAD (iTAAD). sTAAD and is highly correlated with genetics. However, although the incidence of iTAAD is much higher, its monogenic contribution is not yet clear. Here, we sequenced 15 known TAAD genes for 578 iTAAD cases from four cardiac centers in China and found that 10.6% patients with a pathogenic/likely pathogenic (P/LP) variant. Other 7.27% of patients carried variants of uncertain significance in these target genes. We further investigated the correlations among genetics, clinical features, and long-term outcomes. Genetic patients showed younger onset ages (P = 1.31E-13) and larger aortic diameter (P = 1.00E-6), with the youngest age in patients with FBN1 P/LP variants. Monogenic variants were also associated with more aortic segments involved (P = 0.043) and complicated with initial dissection (P = 4.50E-5), especially for genetic patients with non-FBN1 P/LP variants. MACEs occurred in 14.9% patients during follow-up of median 55 months. Genetic status (P = 0.001) and initial dissection (P = 3.00E-6) were two major risk factors for poor prognosis. Early onset age was associated with MACEs in non-genetic cases without initial dissection (P = 0.005). Our study revealed the monogenic contribution in known TAAD genes to iTAAD patients. The genotype-phenotype correlations may complement the risk stratification of iTAAD patients and identification of higher risk subgroups, as well as assist the development of tailored precision medicine in iTAAD.