Mutations in fibrillin-1 (FBN1) were detected in an autosomal dominant Marfan syndrome (MFS) pedigree. The related phenotypes and the significance of mutation screening were discussed. Complete medical and cardiovascular examinations for all pedigree members were performed. Whole exons sequencing (WES) was used to sequence the DNA of the patients and their relatives. The potential pathogenic mutation sites were screened by bioinformatics method. Sanger sequencing was used to verify the mutation sites in the pedigree. The results showed that FBN1 missense mutation was c.6806 T>C in exon 56, resulting in isoleucine being replaced by threonine (p. Ile2269Thr). This mutation has not been reported in Chinese Han population. The occurrence of the mutations strongly correlated with the phenotypes of the patients. The results expand the mutation spectrum of FBN1, and it is helpful to further explore the molecular pathogenesis of MFS and MFS related diseases.