Common Congenital Heart Defects in Turner Syndrome
Bicuspid aortic valve is the most common congenital heart defect in Turner syndrome, occurring in 15-39% of patients, followed by aortic coarctation in 7-21% of cases. 1, 2, 3
Primary Cardiac Malformations
Bicuspid Aortic Valve (Most Common)
- Bicuspid aortic valve affects 15-30% of Turner syndrome patients according to major guidelines, though recent echocardiographic studies using optimized imaging techniques report prevalence as high as 39%. 1, 2, 4, 3
- This represents the single most frequent cardiac anomaly, surpassing the historically reported predominance of coarctation. 5, 3
- A systolic ejection click on physical examination correlates with bicuspid aortic valve in 82% of cases. 5
Aortic Coarctation (Second Most Common)
- Aortic coarctation occurs in 7-18% of Turner syndrome patients, with most recent large cohort studies reporting 21% prevalence. 6, 1, 2, 3
- The typical location is juxtaductal, just distal to the left subclavian artery. 6
- Coarctation is independently associated with increased aortic dissection risk and requires lifelong surveillance. 1, 4
Ascending Aortic Dilation
- Approximately 33% of Turner syndrome patients develop ascending aortic dilation, representing a major cause of premature cardiovascular mortality. 1, 2, 4
- This is an acquired progressive condition rather than a congenital defect per se, but reflects intrinsic aortic wall abnormalities present from birth. 6
Other Structural Defects
- Partial anomalous pulmonary venous drainage occurs at significantly higher rates than in the general population. 7
- Ventricular septal defects, atrial septal defects, and other valve abnormalities occur less frequently but should be screened. 6, 8
- Overall, 50-56% of Turner syndrome patients have some form of structural cardiac anomaly. 2, 3
Critical Diagnostic Approach
Mandatory Initial Evaluation
- All patients with Turner syndrome require comprehensive cardiovascular evaluation at diagnosis with BOTH transthoracic echocardiography AND cardiac MRI. 1, 4
- Echocardiography alone misses critical abnormalities, particularly mid-ascending aortic pathology. 1, 4
- The echocardiogram must include suprasternal and high parasternal windows; failure to obtain these views is associated with missed diagnoses. 3
Karyotype-Specific Patterns
- The 45,X monosomy karyotype is associated with the most severe malformations. 7
- Ring chromosome patterns show very high incidence of bicuspid aortic valve. 7
- X isochromosome patterns may have lower rates of cardiac anomalies. 7
Common Diagnostic Pitfalls
The most critical error is relying solely on transthoracic echocardiography without cardiac MRI, which systematically misses mid-ascending aortic pathology and subtle coarctation. 1, 4
Using absolute aortic measurements without indexing to body surface area (calculating Aortic Size Index) dramatically underestimates dissection risk due to the characteristic short stature in Turner syndrome. 1, 2, 4
Incomplete echocardiographic windows—particularly omitting suprasternal and high parasternal views—results in failure to identify hemodynamically significant lesions. 3