Abstract:  Objective To analyze the gene mutation in a pair of rare twins with mitral valve prolapse and severe regurgitation,and to explore the relationship between the new gene mutation and mitral valve prolapse.Methods Chordae tendineae and blood samples were taken for examination during operation,and analyzed by whole exon sequencing and gene copy number variations(CNV).Results The results of ultrasonography showed that the lesion location and shape of mitral valve were consistent between the two.The anterior and posterior leaflets of mitral valve were slightly lengthy,the tendons were thin,and the left atrium was detached during systole.Gene detection showed that there were mutations in bone morphogenetic protein receptor type-2(BMPR2) gene. Conclusion The mutation of BMPR2 gene exon may be related to mitral valve prolapse.If the role of this gene mutation can be confirmed,it can provide help for clinical diagnosis and treatment in the future.

Key words: mitral valve prolapse, degeneration, BMPR2, gene mutation