BARLOW'S SYNDROME - Also referred to as mitral valve prolapse, systolic click-murmur syndrome, floppy-valve syndrome, and billowing mitral leaflet syndrome. A common, but highly variable (most individuals are asymptomatic), clinical syndrome that has been described in up to 7% of all females in the 14 to 30 age group. There is also an increased familial incidence suggesting an autosomal dominant form of inheritance.