Is bicuspid aortic valve (BAV) hereditary?

Bicuspid Aortic Valve Is Hereditary

Yes, bicuspid aortic valve (BAV) is hereditary with a strong genetic component, demonstrating autosomal dominant transmission in families with high heritability (89%). 1

Genetic Basis of BAV

BAV is the most common congenital heart defect, affecting 0.5-2% of the general population. The evidence strongly supports a genetic basis:

• Studies have demonstrated that BAV can be inherited in families as an autosomal dominant condition 2
• The heritability (h²) of BAV is estimated at 89%, indicating that BAV determination is almost entirely genetic 1
• Approximately 9% of patients have family members who also have bicuspid aortic valves 2
• No single-gene model clearly explains BAV inheritance, with several genes implicated in embryogenesis and cell differentiation associated with BAV/BAV-related aortopathy, but each explaining <5% of cases 2

Clinical Implications of Hereditary BAV

The hereditary nature of BAV has important clinical implications:

• BAV is recognized as a syndrome incorporating valve disorders and aortic wall abnormalities, including aortic dilation, dissection, or rupture 2
• First-degree relatives of BAV patients have an increased risk of:
  • Having BAV themselves
  • Developing thoracic aortic aneurysms even in the absence of BAV 2
  • Aortic dissection (AoD), which occurs in 12.5% of patients with bicuspid valves even with aortic diameter <5 cm 2

Screening Recommendations for Family Members

Based on the hereditary nature of BAV, guidelines recommend:

• First-degree relatives of patients with BAV should be evaluated for the presence of BAV and asymptomatic thoracic aortic disease (Class I, Level of Evidence: C) 2
• Screening by transthoracic echocardiography (TTE) in first-degree relatives of BAV patients with root phenotype or aortopathy is recommended 2
• Because of the variable age of onset of aortic disease in familial thoracic aortic aneurysms and dissections, imaging of family members at risk every 2 years is warranted 2

Management Considerations for BAV Patients

When BAV is diagnosed:

• Complete study of the thoracic aorta is necessary at initial diagnosis 2
• All patients with BAV should have both the aortic root and ascending thoracic aorta evaluated for evidence of aortic dilatation (Class I, Level of Evidence: B) 2
• Surveillance by TTE becomes necessary when the maximum aortic diameter exceeds 40 mm 2
• CCT or CMR of the entire thoracic aorta is recommended at first diagnosis and when the diameter exceeds 45 mm 2

Common Pitfalls and Caveats

• BAV may be asymptomatic for decades before complications develop
• Family members can have thoracic aortic aneurysms even in the absence of BAV 2
• Genetic testing is not indicated for isolated BAV disease but should be reserved for patients with:
  • Syndromic features
  • Family history of aortic disease
  • Aneurysms/dissections of medium-sized arteries other than the thoracic aorta 2
• BAV is associated with other congenital heart defects, including aortic coarctation, ventricular or atrial septal defects, and abnormal mitral valve 1

The high heritability and autosomal dominant inheritance pattern of BAV emphasize the importance of family screening to prevent potentially catastrophic aortic complications in affected individuals.