OBJECTIVE: To determine the types of genetic variants in six Chinese pedigrees affected with Marfan syndrome (MFS) and analyze their clinical characteristics and molecular pathogenesis. METHODS: Six MFS pedigrees presented at the Taizhou Enze Medical Center (Group) between 2017 and 2022 were selected as the study subjects. Clinical data of pedigrees were retrospectively analyzed. Peripheral blood samples were collected from the probands and their family members for the extraction of genomic DNA. Whole exome sequencing (WES) was carried out. Candidate variants of the FBN1 gene were verified by Sanger sequencing. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), pathogenicity of the candidate variants was assessed. AlphaFold3 and PyMOL software were used for homology modeling of the FBN1 protein and analysis of its three-dimensional structure and amino acid sequence conservation. This study was approved by the Medical Ethics Committee of Taizhou Enze Medical Center (Group) (Ethics No. 20231002). RESULTS: Cardiovascular system abnormalities were noted in all pedigrees, ocular abnormalities were present in pedigrees 2 and 5, skeletal system abnormalities were presented in pedigrees 1, and 4 to 6. FBN1 gene mutations were identified in all pedigrees, including c.1957_1958dupGT (p.Asp654fs), c.5014T>A (p.Cys1672Ser), c.8135delC (p.Pro2712fs), c.2302G>T (p.Glu768*), c.3473A>G (p.Glu1158Gly) and c.6169C>T (p.Arg2057*), with each involving a different exon. Four variants were rated as pathogenic, one as likely pathogenic, and one as variant of uncertain significance. Among these, c.5014T>A (p.Cys1672Ser), c.1957_1958dupGT (p.Asp654fs), c.8135delC (p.Pro2712fs), and c.2302G>T (p.Glu768*) were unreported previously. Bioinformatic analysis with SIFT and PolyPhen-2 predicted that the c.5014T>A (p.Cys1672Ser) and c.3473A>G (p.Glu1158Gly) variants were deleterious. Protein homologous sequence alignment analysis revealed that the four novel mutation sites are highly conserved across various species. Homology modeling of the FBN1 protein three-dimensional structure indicated that the six variant sites in the amino acid sequence are all close to hydrogen bonds and may alter the secondary and tertiary structures to varying degrees, thereby confirmed the relationship between the variants and MFS. CONCLUSION Four novel variants of the FBN1 gene have been discovered in this study, which has enriched the mutational and phenotypic spectrum of MFS and provided a basis for disease diagnosis and genetic counseling.
Adolescent ; Adult ; Child ; Female ; Humans ; Male ; Middle Aged ; Young Adult ; China ; East Asian People/genetics* ; Exome Sequencing ; Fibrillin-1/genetics* ; Marfan Syndrome/genetics* ; Mutation ; Pedigree ; Retrospective Studies ; Adipokines

OBJECTIVE: To carry out genetic testing for a child with Marfan syndrome (MFS) and explore its genotype-phenotype correlation. METHODS: Peripheral blood samples of the child and his parents were collected for the extraction of genomic DNA and subjected to whole exome sequencing (WES). Candidate variants were verified by Sanger sequencing. Functional impact of the variant was predicted by using bioinformatic software. RESULTS: The child, a 13-year-old male, has featured Marfanoid habitus, with arm span exceeding his height, tapering fingers and toes, pectus excavatum and scoliosis, but absence of typical cardiovascular system diseases such as aortic dilation, thoracic-abdominal aortic aneurysm, mitral valve prolapse, and lens dislocation. The child has harbored a novel splice site variant c.7383_7413del (p. N2461Kfs*211) of the FBN1 gene, which was not found in his parents and younger brother. The variant was unreported previously. CONCLUSION The novel variant of p. N2461Kfs*211 of the FBN1 gene probably underlay the MFS in this child. Above finding has enriched the genotypic and phenotypic spectrum of MFS.
Male ; Humans ; Marfan Syndrome/genetics* ; Fibrillin-1/genetics* ; Mutation ; Genotype ; Genetic Association Studies

OBJECTIVE: To explore the genetic basis for four patients suspected for Marfan syndrome (MFS). METHODS: Four male patients with suspected MFS and their family members who were treated at West China Second Hospital of Sichuan University from September 12, 2019 to March 27, 2021 were selected as the study subjects. Peripheral venous blood samples were collected from the patients and their parents or other pedigree members for the extraction of genomic DNA. Whole exome sequencing was carried out, and candidate variants were validated by Sanger sequencing. The pathogenicity of the variants was determined based on the guidelines from the American College of Medical Genetics and Genomics (ACMG). RESULTS: Genetic testing revealed that all four patients have harbored variants of the FBN1 gene, including c.430_433del (p.His144fs) deletional variant in exon 5, c.493C>T (p.Arg165*) nonsense variant in exon 6, c.5304_5306del (p.Asp1768del) deletional variant in exon 44 and c.5165C>G (p.Ser1722Cys) missense variant in exon 42. According to the ACMG guidelines, the c.430_433del and c.493C>T were classified as pathogenic variants (PVS1+PM2_Supporting+PP4; PVS1+PS1+PS2+PM2_Supporting+PP4). c.5304_5306del and c.5165C>G were classified as likely pathogenic variants (PS2+PM2_Supporting+PM4+PP4; PS2_Moderate+PS1+PM1+PM2_Supporting). CONCLUSION The c.430_433del and c.5304_5306del variants of the FBN1 gene identified in this study were unreported previously. Above results have enriched the variation spectrum of the FBN1 gene and provided a basis for genetic counseling and prenatal diagnosis of patients with MFS and acromicric dysplasia.
Female ; Pregnancy ; Humans ; Male ; Exons ; China ; Family ; Genetic Counseling ; Genetic Testing ; Marfan Syndrome/genetics* ; Mutation ; Fibrillin-1/genetics*

OBJECTIVE: To identify whether naringenin plays a protective role during thoracic aneurysm formation in Marfan syndrome. METHODS: To validate the effect of naringenin, Fbn1^C1039G/+ mice, the mouse model of Marfan syndrome, were fed with naringenin, and the disease progress was evaluated. The molecular mechanism of naringenin was further investigated via in vitro studies, such as bioluminescence resonance energy transfer (BRET), atomic force microscope and radioligand receptor binding assay. RESULTS: Six-week-old Fbn1^C1039G/+ mice were fed with naringenin for 20 weeks. Compared with the control group, naringenin significantly suppressed the aortic expansion [Fbn1^C1039G/+ vs. Fbn1^C1039G/++naringenin: (2.49±0.47) mm, n=18 vs. (1.87±0.19) mm, n=22, P < 0.05], the degradation of elastin, and the expression and activity of matrix metalloproteinase 2 (MMP2) and MMP9 in the ascending aorta of Fbn1^C1039G/+ mice. Besides, treatment with naringenin for 6 weeks also attenuated the disease progress among the 20-week-old Fbn1^C1039G/+ mice with established thoracic aortic aneurysms [Fbn1^C1039G/+ vs. Fbn1^C1039G/++naringenin: (2.24±0.23) mm, n=8 vs. (1.90±0.17) mm, n=8, P < 0.05]. To understand the underlying molecular mechanisms, we examined the effects of naringenin on angiotensin Ⅱ type 1 receptor (AT1) signaling and transforming growth factor-β (TGF-β) signaling respectively, which were the dominant signaling pathways contributing to aortopathy in Marfan syndrome as previously reported. The results showed that naringenin decreased angiotensin Ⅱ (Ang Ⅱ)-induced phosphorylation of protein kinase C (PKC) and extracellular regulating kinase 1/2 (ERK1/2) in HEK293A cell overexpressing AT1 receptor. Moreover, naringenin inhibited Ang Ⅱ-induced calcium mobilization and uclear factor of activated T-cells (NFAT) signaling. The internalization of AT1 receptor and its binding to β-arrestin-2 with Ang Ⅱ induction were also suppressed by naringenin. As evidenced by atomic force microscope and radioligand receptor binding assay, naringenin inhibited Ang Ⅱ binding to AT1 receptor. In terms of TGF-β signaling, we found that feeding the mice with naringenin decreased the phosphorylation of Smad2 and ERK1/2 as well as the expression of TGF-β downstream genes. Besides, the serum level of TGF-β was also decreased by naringenin in the Fbn1^C1039G/+ mice. Furthermore, we detected the effect of naringenin on platelet, a rich source of TGF-β, both in vivo and in vitro. And we found that naringenin markedly decreased the TGF-β level by inhibiting the activation of platelet. CONCLUSION Our study showed that naringenin has a protective effect on thoracic aortic aneurysm formation in Marfan syndrome by suppressing both AT1 and TGF-β signaling.
Angiotensin II/metabolism* ; Animals ; Aortic Aneurysm, Thoracic/prevention & control* ; Calcium/metabolism* ; Disease Models, Animal ; Elastin/metabolism* ; Fibrillin-1/metabolism* ; Flavanones ; Marfan Syndrome/metabolism* ; Matrix Metalloproteinase 2 ; Matrix Metalloproteinase 9 ; Mice ; Mice, Inbred C57BL ; Protein Kinase C/metabolism* ; Receptor, Angiotensin, Type 1/metabolism* ; Transforming Growth Factor beta/metabolism* ; Transforming Growth Factors/metabolism* ; beta-Arrestins/metabolism*

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.
Fibrillin-1/genetics* ; Humans ; Infant, Newborn ; Marfan Syndrome/therapy* ; Mutation

OBJECTIVE: To explore the genetic basis for a child featuring unexplained rapid growth and heart malformation. METHODS: Whole exome sequencing (WES)was carried out for the patient. Suspected variant was verified by Sanger sequencing and subjected to bioinformatic analysis. RESULTS: The child was found to harbor a novel de novo c.5846_5848delATA (p. N1949del) variant in exon 48 of the FBN1 gene, which was predicted to be pathogenic by Mutation Taster. The patient was ultimately diagnosed with Marfan syndrome. CONCLUSION Above finding has enriched the spectrum of genetic variants associated with Marfan syndrome. WES has provided a powerful tool for the diagnosis of rare diseases.
Child ; Exons ; Fibrillin-1/genetics* ; Heart Defects, Congenital ; Humans ; Marfan Syndrome/genetics* ; Mutation ; Sequence Deletion ; Whole Exome Sequencing

OBJECTIVE: To detect mutations of fibrillin-1 (FBN1) gene in two pedigrees affected with Marfan syndrome (MFS). WETHODS: Peripheral blood samples were collected from MFS patients and their healthy family members for extracting genomic DNA. All of the 65 exons of the FBN1 gene were analyzed by next-generation sequencing. PolyPhen-2 and SIFT was used to predict structural and functional changes in FBN1 protein. RESULTS: Patients from both pedigrees presented ocular and skeletal manifestations suggestive of MFS. Two novel heterozygous mutations of the FBN1 gene, including c.1879C>T (p.R627C) in exon 16 and c.2584T>C (p.C862R) in exon 22, were identified. The same mutations were not found among unaffected members. By bioinformatic analysis, the mutations may affect the structure and function of the FBN1 protein. CONCLUSION The c.1879C>T and c.2584T>C mutations of the FBN1 gene probably account for the disease in the two pedigrees, respectively. Identification of the c.2584T>C has enriched the spectrum of FBN1 gene mutations.
DNA Mutational Analysis ; Exons ; Fibrillin-1 ; genetics ; Fibrillins ; Humans ; Marfan Syndrome ; genetics ; Mutation ; Pedigree

No abstract available.
Bone Diseases, Developmental/diagnosis/drug therapy/*genetics ; Child ; Fibrillin-1/*genetics ; Hand/diagnostic imaging ; Heterozygote ; Human Growth Hormone/therapeutic use ; Humans ; Limb Deformities, Congenital/diagnosis/drug therapy/*genetics ; Male ; Pelvis/diagnostic imaging

OBJECTIVETo screen for mutations of fibrillin-1 (FBN1) gene in 4 patients with Marfan syndrome in order to provide prenatal diagnosis and genetic counseling.

METHODSPotential mutations of the FBN1 gene in the probands were detected with PCR and DNA sequencing. Subsequently, genomic DNA was extracted from amniotic fluid sampled between 18 to 20 weeks gestation. The mutations were confirmed with denaturing high-performance liquid chromatography - robust microsatellite instability (DHPLC-MSI) analysis with maternal DNA as reference. The products were further analyzed by direct sequencing and BLAST search of NCBI database.

RESULTSAn IVS46+1G>A substitution was identified in patient A at +1 position of intron 46 of the FBN1 gene. Two novel missense mutations were respectively discovered at positions +4453 of intron 35 in patient B (Cys1485Gly) and position +2585 of intron 21 in patient C (Cys862Tyr). In patient D, a novel deletion (c.3536 delA) was found at position +3536 of intron 28. In all of the 4 cases, the same mutations have been identified in the fetuses.

CONCLUSIONFBN1 gene analysis can provide accurate diagnosis of Marfan syndrome, which can facilitate both prenatal diagnosis and genetic counseling.

Adult ; Base Sequence ; DNA Mutational Analysis ; Female ; Fibrillin-1 ; Fibrillins ; Humans ; Introns ; Male ; Marfan Syndrome ; diagnosis ; embryology ; genetics ; Microfilament Proteins ; genetics ; Molecular Sequence Data ; Mutation, Missense ; Pregnancy ; Prenatal Diagnosis ; Sequence Deletion

OBJECTIVETo detect pathogenic mutations in Marfan syndrome (MFS) using an Ion Torrent Personal Genome Machine (PGM) and to validate the result of targeted next-generation semiconductor sequencing for the diagnosis of genetic disorders.

METHODSPeripheral blood samples were collected from three MFS patients and a normal control with informed consent. Genomic DNA was isolated by standard method and then subjected to targeted sequencing using an Ion Ampliseq(TM) Inherited Disease Panel. Three multiplex PCR reactions were carried out to amplify the coding exons of 328 genes including FBN1, TGFBR1 and TGFBR2. DNA fragments from different samples were ligated with barcoded sequencing adaptors. Template preparation and emulsion PCR, and Ion Sphere Particles enrichment were carried out using an Ion One Touch system. The ion sphere particles were sequenced on a 318 chip using the PGM platform. Data from the PGM runs were processed using an Ion Torrent Suite 3.2 software to generate sequence reads. After sequence alignment and extraction of SNPs and indels, all the variants were filtered against dbSNP137. DNA sequences were visualized with an Integrated Genomics Viewer. The most likely disease-causing variants were analyzed by Sanger sequencing.

RESULTSThe PGM sequencing has yielded an output of 855.80 Mb, with a > 100 × median sequencing depth and a coverage of > 98% for the targeted regions in all the four samples. After data analysis and database filtering, one known missense mutation (p.E1811K) and two novel premature termination mutations (p.E2264X and p.L871FfsX23) in the FBN1 gene were identified in the three MFS patients. All mutations were verified by conventional Sanger sequencing.

CONCLUSIONPathogenic FBN1 mutations have been identified in all patients with MFS, indicating that the targeted next-generation sequencing on the PGM sequencers can be applied for accurate and high-throughput testing of genetic disorders.

Base Sequence ; Computational Biology ; Fibrillin-1 ; Fibrillins ; Genomics ; High-Throughput Nucleotide Sequencing ; methods ; Humans ; Marfan Syndrome ; diagnosis ; genetics ; Microfilament Proteins ; genetics ; Mutation ; Semiconductors