Rare diseases · Sign or symptom
Bicuspid aortic valve
Aortic valve has two leaflets rather than three
HP:0001647
What it means
The presence of an aortic valve with two instead of the normal three cusps (flaps). Bicuspid aortic valvue is a malformation of a commissure (small space between the attachment of each cusp to the aortic wall) and the adjacent parts of the two corresponding cusps forming a raphe (the fused area of the two underdeveloped cusps turning into a malformed commissure between both cusps; the raphe is a fibrous ridge that extends from the commissure to the free edge of the two underdeveloped, conjoint cusps).
A normal aortic valve is composed of three aortic-valve cusps, each semilunar in appearance. The leaflets are housed within a small dilatation of the proximal aorta associated with each cusp, called the sinuses of Valsalva or aortic sinuses, and their association with the respective coronary ostia identifies them: left, right, and non-coronary sinuses. Each cusp is attached to the wall of the aorta by the outward edges of its semicircular border, and the attachment point between each leaflet is called a commissure [PMID:24827036].
Rare diseases that can present with this48
Always100%
2Common30–79%
5Sometimes5–29%
30- 45,X/46,XY mixed gonadal dysgenesis
- Aortic arch interruption
- Congenital alveolar capillary dysplasia
- Coronary arterial fistula
- Facial dysmorphism-developmental delay-behavioral abnormalities syndrome due to 10p11.21p12.31 microdeletion
- Familial thoracic aortic aneurysm and aortic dissection
- Fixed subaortic stenosis
- FLNA-related X-linked myxomatous valvular dysplasia
and 22 more in this range
Rare1–4%
10- Cardiac diverticulum
- Craniofaciofrontodigital syndrome
- Houge-Janssens syndrome type 1
- Kyphoscoliotic Ehlers-Danlos syndrome
- Laubry-Pezzi syndrome
- PURA-related severe neonatal hypotonia-seizures-encephalopathy syndrome
- Rubinstein-Taybi syndrome due to 16p13.3 microdeletion
- Rubinstein-Taybi syndrome due to CREBBP mutations
and 2 more in this range
The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.
Part of the broader category
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Start free with EleplanThis page uses the Human Phenotype Ontology (2026-06-23) — Human Phenotype Ontology Consortium, hpo.jax.org. Disease associations from Orphanet (INSERM), CC BY 4.0. Content is educational and is not medical advice.