Successful Mitral Valve Replacement in an Infant with Neonatal Marfan Syndrome due to a Novel Missense Mutation of the <i>FBN1</i> Gene

Marfan syndrome is an autosomal dominant genetic disorder of the fibrous connective tissue caused by pathogenic mutations in the fibrillin-1 gene. Neonatal Marfan syndrome is a rare type of Marfan syndrome that is genotypically and phenotypically different from classical Marfan syndrome and has a poor prognosis. Most patients with neonatal Marfan syndrome die during infancy due to severe and rapidly progressive cardiovascular disorders. Here, we present a case of an 11-year-old girl with neonatal Marfan syndrome due to a novel missense mutation in exon 27 of the fibrillin-1 gene. Her condition was critical due to progressive mitral and tricuspid regurgitation. Mitral valve replacement, performed at the age of 6 months, improved her critical condition. Our case suggests that early mitral valve replacement may lead to better outcomes in patients with neonatal Marfan syndrome.