Prenatal diagnosis of Marfan syndrome by fetal echocardiography: A case report and review of cardiovascular manifestations

Current status and challenges in prenatal and neonatal screening, diagnosis, and management of congenital heart disease in China

Congenital heart disease (CHD), a wide spectrum of diseases with varied outcomes, is the most common congenital malformation worldwide. In this Series of three papers, we describe the burden of CHD in China; the development of screening, diagnosis, treatment, and follow-up strategies; and challenges associated with the disease. We also propose solutions and recommendations for policies and actions to improve the outcomes of CHD. In the first paper in this Series, we focus on prenatal and neonatal screening, diagnosis, and management of CHD. Based on advanced international knowledge, the Chinese Government has developed a network system comprising prenatal screening, diagnosis of CHD subtypes, specialist consultation appointments, and treatment centres for CHD. A new professional discipline, fetal cardiology, has been formed and rapidly developed. Consequently, the overall coverage of prenatal and neonatal screening and the accuracy of CHD diagnoses have gradually improved, and the neonatal CHD mortality rate has decreased substantially. However, China still faces several challenges in the prevention and treatment of CHD, such as insufficient diagnostic capabilities and unqualified consultation services in some regions and rural areas. TRANSLATION: For the Chinese translation of the abstract see Supplementary Materials section.

[Latest advances in the diagnosis and treatment of Marfan syndrome]

Marfan syndrome (MFS) is a multisystem connective tissue disease with autosomal dominant inheritance. It is mainly caused by FBN1 gene mutation and often has different clinical manifestations. Neonatal MFS is especially rare with severe conditions and a poor prognosis. At present, there is still no radical treatment method for MFS, but early identification, early diagnosis, and early treatment can effectively prolong the life span of patients. This article reviews the latest advances in the diagnosis and treatment of MFS.

Functional Analysis of an Intronic FBN1 Pathogenic Gene Variant in a Family With Marfan Syndrome

Marfan syndrome (MFS) is an autosomal dominant connective tissue disorder that canonically affects the ocular, skeletal, and cardiovascular system, in which aortic tear and rupture is the leading cause of death for MFS patients. Genetically, MFS is primarily associated with fibrillin-1 (FBN1) pathogenic variants. However, the disease-causing variant in approximately 10% of patients cannot be identified, partly due to some cryptic mutations that may be missed using routine exonic sequencing, such as non-coding intronic variants that affects the RNA splicing process. We present a 32-year female with typical MFS systemic presentation that reached to a clinical diagnosis according to the revised Ghent nosology. We performed whole-exome sequencing (WES) but the report failed to identify known causal variants when analyzing the exonic sequence. However, further investigation on the exon/intron boundaries of the WES report revealed a candidate intronic variant of the fibrillin 1 (FBN1) gene (c.248-3 C>G) that predicted to affect the RNA splicing process. We conducted minigene splicing analyses and demonstrated that the c.248-3 C>G variant abolished the canonical splicing site of intron 3, leading to activation of two cryptic splicing sites and causing insertion (c.248-1_248-2insAG and c.248-1_248-282ins). Our study not only characterizes an intronic variant to the mutational spectrum of the FBN1 gene in MFS and its aberrant effect on splicing, but highlights the importance to not neglect the exon/intron boundaries when reporting and assessing WES results. We point out the need of conducting functional analysis to verify the pathogenicity of intronic mutation, and the opportunity to re-consider the standard diagnostic approaches in cases of clinically diagnosed MFS with normal or variant of unknown significance genetic results.