Table 1.

Main characteristics distinguishing non-syndromic and syndromic mitral valve prolapse.

Characteristics	Non-syndromic MVP	Syndromic MVP
Hereditary transmission	Sporadic or familial forms	Defined genetic transmission from known syndromes (most often CTDs)
Prevalence	More common (about 2% of general population)	Less common (1:5,000 births)
Age at diagnosis	Middle aged adults	Young age/at birth
Clinical manifestation	Isolated, primary mitral regurgitation	Mitral regurgitation associated with other organs involvement according to the specific syndrome
Mutations	Multifactorial genetic alterations and external factors	Specific gene mutations
Molecular pathways involved	TGF-β pathway activation Upregulation of adherence molecules	TGF-β pathway overexpression Nuclear accumulation of SMAD2
Histological phenotypes	Accumulation of myxoid ECM in leaflets and chordae tendineae	Proliferation of valvular interstitial cells Defect in collagen fibers Calcium accumulation

CTD, connective tissue disease; ECM, extracellular matrix; TGF-β, transforming growth factor-beta.