This is from our own Reference Sources,
http://www.valvereplacement.com/forums/showthread.php?t=11603supplied by PJmomrunner back in May, 2005.
The thread is titled Bicuspid and Tissue Reference Links.
I'm quoting the first paragraph:
The population frequency of a bicuspid aortic valve is [almost equal to]0.9% to
1.36%,1-3 with a 2:1 male:female ratio. It is likely that the presence of a
bicuspid aortic valve has a genetic basis, with the pattern of transmission in
some families suggesting an autosomal dominant pattern of inheritance.4,5
Epidemiological data from the Baltimore-Washington Infant Study demonstrated the
familial clustering of left heart obstructive lesions (including coarctation of
the aorta, aortic valve stenosis, and hypoplastic left heart syndrome).6 More
recently, the increased risk of identifying a bicuspid aortic valve in the
parent or sibling of the proband with any form of left heart obstructive lesion
was described.7 By inference, this also suggests the potential identification of
a congenitally malformed aortic valve in the presence a family member with a
more complex congenital heart lesion. In addition, a bicuspid aortic valve is
present in >50% of patients with aortic coarctation 8 and in 10% to 12% of women
with Turner syndrome.9 The specific genetic locus and protein abnormality in
patients with a bicuspid aortic valve have not yet been identified, however.