Rare diseases Xagena

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Patients with bicuspid aortic valve without Marfan syndrome: identification of fibrillin 1 gene mutations

Bicuspid aortic valve ( BAV ) is the most frequent congenital heart disease with frequent involvement in thoracic aortic dilatation, aneurysm and dissection. Although BAV and Marfan syndrome ( MFS ) share some clinical features, and some MFS patients with BAV display mutations in FBN1, the gene encoding fibrillin-1, the genetic background of isolated BAV is poorly defined.

Ten consecutive BAV patients [ 8 men, age range 24–42 years ] without Marfan syndrome were clinically characterized. BAV phenotype and function, together with evaluation of aortic morphology, were comprehensively assessed by Doppler echocardiography.
Direct sequencing of each FBN1 exon with flanking intron sequences was performed on eight patients.

Researchers at University of Florence ( Italy ) have detected three FBN1 mutations in two patients ( aged 24 and 25 years ) displaying aortic root aneurysm greater than or equal to 50 mm and moderate aortic regurgitation.
In particular, one patient had two mutations ( p.Arg2726Trp and p.Arg636Gly ) one of which has been previously associated with variable Marfanoid phenotypes.
The other patient showed a pArg529Gln substitution reported to be associated with an incomplete MFS phenotype.

The present findings enlarge the clinical spectrum of isolated BAV to include patients with BAV without Marfan syndrome who have involvement of FBN1 gene.
These results underscore the importance of accurate phenotyping of BAV aortopathy and of clinical characterization of BAV patients, including investigation of systemic connective tissue manifestations and genetic testing. ( Xagena )

Pepe G et al, BMC Medical Genetics 2014, 15:23