A Familial Case of Marfan Syndrome

Introduction Marfan syndrome (MFS) is a connective tissue disorder with autosomal dominant inheritance, always caused by pathogenic variants in the fibrillin-1 gene (FBN1). This case report presents a familial occurrence of MFS involving a mother and her two children. The case was chosen for its clinical relevance in illustrating the phenotypic variability within the same family and emphasizing the importance of genetic confirmation in guiding management. Case Presentation We report a case of 2 siblings, a 17-year-old female (index patient) and her 14-year-old brother, both exhibiting clinical features suggestive of MFS. The index patient was born at 37 weeks (2270 g), while her brother was born at full term via C-section (3110 g). Both presented with congenital clubfoot, scoliosis, accelerated growth, bilateral pes cavus, positive thumb and wrist signs, horizontal striae, an arm span-to-height ratio greater than 1.05, and reduced elbow extension. Their mother, under medical supervision for aortic dilatation and pes cavus, previously underwent surgical correction for pectus carinatum. Cardiovascular assessment confirmed aortic root dilatation only in the brother, fulfilling a major criterion for MFS based on the revised Ghent criteria [1,2]. Given the strong family history and clinical presentation, genetic testing identified a likely pathogenic FBN1 variant in all 3 family members, confirming the diagnosis of MFS. Discussion Genetic confirmation is particularly valuable in patients at risk for progressive aortic complications. This case underscores the variable phenotypic expression of MFS, highlighting the need for a combined clinical and genetic approach to optimize diagnosis, and long-term follow-up. Conclusions The diagnosis of MFS in these patients highlights the importance of integrating clinical criteria with genetic testing. While the 14-year-old male met the Ghent criteria through aortic root dilatation and systemic features, the 17-yearold female's diagnosis relied heavily on genetic confirmation of a likely pathogenic FBN1 variant. Genetic testing was crucial for establishing the diagnosis. This combined approach ensures early detection and preventive care, essential for managing the complications associated with MFS.