FBN1 isoform expression varies in a tissue and development-specific fashion

► We evaluate splicing in FBN1, mutations in which cause Marfan syndrome. ► We report two FBN1 splice variants that are both predicted to produce non-functional protein. ► The expression of one isoform, 57A-FBN1, varies between tissues and with development. ► 57A-FBN1 represents a significant proportion of FBN1 expression. ► 57A-FBN1 may regulate fibrillin expression and disease severity.