Clinical manifestations and genetic analysis of 4 patients with variants of FBN1 gene / 中华医学遗传学杂志

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.

Analysis of a child with Marfan syndrome due to a novel variant of FBN1 gene / 中华医学遗传学杂志

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.

Latest advances in the diagnosis and treatment of Marfan syndrome / 中国当代儿科杂志

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.

A de novo mutation leading to Marfan syndrome in a case / 中华医学遗传学杂志

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.

Identification of a novel FBN1 variant in a pedigree affected with Marfan syndrome / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a pedigree affected with Marfan syndrome (MFS).@*METHODS@#Clinical data of the patients was collected. With genomic DNA extracted from peripheral blood samples, potential mutation was detected by targeted exome sequencing. Candidate variants were validated by Sanger sequencing and bioinformatic analysis.@*RESULTS@#Targeted exome sequencing and Sanger sequencing revealed a missense c.649T to C(p.Trp217Arg) variant in the exon 7 of FBN1 gene, which was unreported previously. Bioinformatics analysis suggested that the variant can cause amino acid replacement and affect the structure and function of fibrillin-1.@*CONCLUSION@#A novel missense variant of the FBN1 gene was identified, which probably underlies the autosomal dominant MFS in this pedigree.

Analysis of FBN1 gene mutations in two pedigrees affected with Marfan syndrome / 中华医学遗传学杂志

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.

A c.3037G>A mutation in FBN1 gene causing Marfan syndrome with an atypically severe phenotype / Mutación c.3037G>A en el gen FBN1 causa sindrome de Marfan con fenotipo atípico severo

Marfan syndrome is a pleiotropic connective tissue disease inherited as an autosomal dominant trait, mostly caused by mutations in the FBN1 gene, which is located on chromosome 15q21.1 and encoding fibrillin 1. We report a case of Marfan syndrome presen ting with severe ocular and systemic manifestations, such as cardiac congenital anomalies. The patient underwent a multidisciplinary approach and his clinical diagnosis was associated with a c.3037G>A mutation in the FBN1 gene. Identification of this genetic alteration should instigate a prompt multidisciplinary assessment and monitoring, in order to prevent devasta ting consequences such as cardiac and ocular phenotype. Molecular modeling of the mutation highlighted the importance of the preservation of the calcium-dependent structure of an epidermal-growth-factor-like domain of fibrillin-1 and consequently the microfibrillar formation process. This report aims to highlight the importance of an early clinical and molecular diagnosis and once more, the importance of the multidisciplinary approach of this genetic entity.

El síndrome de Marfan es una enfermedad pleitrópica del tejido conjuntivo que exhibe un patrón de herencia autosómico dominante, en su mayoría causado por mutacio nes en el gen FBN1 , que se encuentra en el cromosoma 15q21.1 y codifica a la fibrilina 1. Se presenta un caso de síndrome de Marfan que cursa con manifestación sistémica severa cardíaca y principlamente ocular. El paciente presentó una valoración multidisciplinaria y su diagnóstico clínico fue asociado con la mutación c.3037G>A en el gen FBN1 . La identificación de esta alteración genética debe promover una pronta evaluación y supervisión con el fin de evitar las desvastadoras consecuencias, tales como el fenotipo cardíaco y ocular. El modelado comparativo de proteínas resalta la importancia de la conservación de la estructura del dominio de la fibrilina-1 dependiente de calcio similar al factor de crecimiento epidérmico y por lo tanto el proceso de formación microfibrilar. Este informe tiene como objetivo resaltar la importancia de un diagnóstico clínico y molecular temprano y el enfoque multidisciplinariode esta entidad genética.

Acromicric Dysplasia Caused by a Novel Heterozygous Mutation of FBN1 and Effects of Growth Hormone Treatment

No abstract available.

Revisión Bibliográfica y Presentación de un Caso: Síndrome de Marfán / Bibliographic Review and Presentation of a Case: Marfán Syndrome

El síndrome de Marfán es una patología poco común, causada por una mutación genética de fibrilina 1, imprescindible para la síntesis de fibras elásticas del tejido conectivo. Se caracteriza por una alta penetrancia y mar-cada heterogeneidad fenotípica. Entre las diferentes manifestaciones clínicas, la afectación cardiovascular merece una consideración especial, debido a su impacto en el pronóstico. El diagnóstico requiere una evaluación clínica completa de múltiples órganos y sistemas; por su ampliada sintomatología, la toma de decisiones es compleja, por tanto, cuando se sospeche síndrome de Marfán debe apli-carse la revisión de los criterios de Ghent. Si el diagnóstico es confirmado, debe iniciarse tempranamente su manejo multidisciplinario con un seguimiento minucioso, ya que se dis-pone de tratamientos farmacológicos y qui-rúrgicos que mejoran la esperanza de vida.Se reporta un caso clínico, con la revisión de las manifestaciones clínicas, criterios diagnósticos y manejo.

Marfan syndrome is a rare disease, caused by a genetic mutation of fibrillin-1, essential for the synthesis of connective tissue elastic fibers. It is characterized by a high penetran-ce and a marked phenotypic heterogeneity. Among the different clinical manifestations, cardiovascular involvement deserves a spe-cial consideration because of their impact on prognosis.The diagnosis requires a complete medical evaluation of multiple organs and systems; with expanded symptoms where the decision making is complex, so when Marfan syndro-me is suspected should be applied the revi-sed criteria of Ghent. If the diagnosis is confir-med, it must start early with its multidisciplinary approach carefully monitored because there are pharmacological and surgical treatments that improve life expectancy.Finally a case is reported, with the review of clinical manifestations, diagnostic criteria and management.

Síndrome de Marfan, mutaciones nuevas y modificadoras del gen FBN1 / Síndrome de Marfan, mutaciones nuevas y modificadoras del gen FBN1

El síndrome de Marfan (SM) es un trastorno sistémico causado por mutaciones en la proteína de la matriz extracelular fibrilina 1 (FBN1). Con un patrón de herencia autosómico dominante, los pacientes se caracterizan por presentar compromiso ocular, cardiovascular y esquelético dentro de un espectro clínico variable. Se ha sugerido que la variabilidad fenotípica intrafamiliar e interfamiliar característica del síndrome ocurre por la asociación de otras mutaciones denominadas modificadoras (driver mutations). Si bien hay claridad acerca de la causalidad genética clásica de la enfermedad, las mutaciones modificadoras descritas recientemente aún no están bien dilucidadas. Se presenta un caso de SM con una mutación no descrita previamente en el gen de la fibrilina 1; se aplica la nosología de Ghent revisada y se analiza el papel de esta mutación nueva y de las mutaciones modificadoras en la génesis de la enfermedad.

Marfan syndrome (MS) is a systemic disorder caused by mutations in the extracellular matrix protein fibrillin 1 (FBN1). With a dominant autosomal pattern, MS patients are characterized by ocular, cardiovascular and skeletal involvement, all within a variable clinical spectrum. It has been suggested that the intrafamilial and interfamilial phenotypic variability, characteristic of the syndrome, occurs by the association of other mutations called driver mutations. Even though there is a clear genetic causation, the recently described driver mutations are not yet fully elucidated. We present a MS case with a mutation not previously described in the fibrilin 1 gene, applying the revised Ghent nosology and analyzing the role of this new mutation and of the driver mutations in the genesis of the disease.

Estrategias terapéuticas de aneurisma abdominal en síndrome de marfan a propósito de un caso

Se presenta el caso de una paciente que acude aconsulta externa del Hospital Vicente Corral Moscosocon diagnóstico de aneurisma de aorta abdominalrealizado mediante tomografía, además se observaque la paciente presenta un biotipo compatiblecon Síndrome de Marfan lo que constituye undesafío diagnóstico y terapéutico. El Síndrome deMarfan se presenta en 1 a 3 casos en cada 10.000pacientes y es causado por defectos en un gen llamado fibrilina-1, el cual juega un papel importantepara la síntesis del tejido conectivo del cuerpoademás de acompañarse de mal formaciones cardiacas y vasculares

It is presented a case of a patient who attends out-patient consultation at the Vicente Corral Moscosohospital with a diagnosis of abdominal aorticaneurysm which was identified through tomography.Besides, the patient shows a biotype compatiblewith Marfan syndrome which constitutes a challengefor diagnosis and therapy. Marfan syndrome ispresent in 1 to 3 cases out of 10,000 patients, andit is caused by defects in a gene called fibrillin-1. Fi-brillin-1 plays an important role for the connectivetissue synthesis of the body; accompanied withcardiac and vascular malformations as well

Detection of pathogenic mutations in Marfan syndrome by targeted next-generation semiconductor sequencing / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To 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.</p><p><b>METHODS</b>Peripheral 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.</p><p><b>RESULTS</b>The 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.</p><p><b>CONCLUSION</b>Pathogenic 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.</p>

Mutation analysis and prenatal diagnosis of FBN1 gene mutations for four patients with Marfan syndrome / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To screen for mutations of fibrillin-1 (FBN1) gene in 4 patients with Marfan syndrome in order to provide prenatal diagnosis and genetic counseling.</p><p><b>METHODS</b>Potential 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.</p><p><b>RESULTS</b>An 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.</p><p><b>CONCLUSION</b>FBN1 gene analysis can provide accurate diagnosis of Marfan syndrome, which can facilitate both prenatal diagnosis and genetic counseling.</p>

Molecular analysis for diagnosis of Marfan syndrome and Marfan-associated disorders / 中华医学杂志(英文版)

Marfan syndrome is a systemic disorder of connective tissue, caused by mutations in the FBN1, TGFBR1 or TGFBR2 genes. This syndrome is characterized by involvement of three major systems, skeletal, ocular, and cardiovascular. The continuing improvements in molecular biology and increasing availability of molecular diagnosis in clinical practice allow recognition of Marfan syndrome in patients with incomplete phenotypes. Additionally, molecular analyses could also be used for preimplantation genetic diagnosis. The identification of a mutation allows for early diagnosis, prognosis, genetic counseling, preventive management of carriers and reassurance for unaffected relatives. The importance of knowing in advance the location of the putative family mutation is highlighted by its straightforward application to prenatal and postnatal screening.

Identification of a novel lethal fibrillin-1 gene mutation in a Chinese Marfan family and correlation of 3' fibrillin-1 gene mutations with phenotype / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Mutations in the fibrillin-1 gene have been identified in patients with Marfan syndrome (MFS). This study aimed to identify the molecular defects in the fibrillin-1 gene in a Chinese family with Marfan syndrome, accompanied by aortic aneurysms/dissection.</p><p><b>METHODS</b>Two patients and one non-carrier in the family underwent complete physical, ophthalmic, and cardiovascular examinations. Genomic DNA was extracted from leukocytes of venous blood of these individuals in the family as well as 50 healthy normal controls. Polymerase chain reaction amplification and direct sequencing of all 65 coding exons of fibrillin-1 gene were analyzed.</p><p><b>RESULTS</b>We found a novel mutation (c.8547T > G, p.Tyr2849X) in exon 65 of fibrillin-1 gene in a Chinese proband with Marfan syndrome, accompanied by aortic aneurysms/dissection. Sudden death at a young age of affected members was seen due to aortic aneurysms/dissection. By evaluating genotype-phenotype correlations of patients with mutations in the 3' end of fibrillin-1 gene (exons 64 and 65), we also found that the presence of nonsense mutations occurring in exons 64 and 65 appeared to be an indicator of early-onset aortic risk and sudden death.</p><p><b>CONCLUSIONS</b>These results expand the mutation spectrum of fibrillin-1 gene and help in the study of the molecular pathogenesis of Marfan syndrome, indicating that mutations occurring in the 3' end of fibrillin-1 gene may play an independent functional role in the pathogenesis of Marfan syndrome.</p>

The expression of fibrillin 1 in pathologic scars and its significance / 中华整形外科杂志

<p><b>OBJECTIVE</b>To probe into the mechanism of fibrillin 1 in pathologic scar, by examining the expressions of fibrillin 1 and TGF-beta1 as well as their correlations in the tissues of keloid, hypertrophic scar and normal skin.</p><p><b>METHODS</b>The tissues of keloid, hypertrophic scar and normal skin were tested. RT-PCR was used to assess the mRNA expression levels of the aimed genes. The distribution of fibrillin 1 in scars and normal skin was examined by immunohistochemistry staining.</p><p><b>RESULTS</b>The mRNA level of fibrillin 1 in keloid (0.802 +/- 0.116) was increased by 218.25% (P < 0.01) than that in normal skin (0.252 +/- 0.067). The expression of the gene in hypertrophic scar (0.628 +/- 0.144) was higher by 149.21% (while, P > 0.05) than that in normal skin. The expression of TGF-beta1 in keloid and hypertrophic scar were more than that in normal skin. The expression of fibrillin 1 was related to that of TGF-beta1 positively (r = 0.820, P < 0.01). Fibrillin 1 protein was stained positively in basic membranes, endothelial cells, fibroblasts and extracellular matrix of skin tissues. In dermal, the protein levels of fibrillin 1 in keloid (0.117 +/- 0.042) was decreased than those in normal skin (0.185 +/- 0.043) and hypertrophic scar (0.181 +/- 0.048), the inhibition rates were 36.76%, 35.36% respectively (both P < 0.01).</p><p><b>CONCLUSIONS</b>The expression of fibrillin 1 in keloid was changed and related to the expression of TGF-beta1 positively, which appears that fibrillin 1 was a cicatrix specific gene. Fibrillin 1 might play an important role in the formation of keloid.</p>

Expressions of fibrillin-1, elastin and matrix metalloproteinase-1 and -9 in chronic actinic dermatitis in elderly patients / 南方医科大学学报

<p><b>UNLABELLED</b>To investigate the expressions of fibrillin-1, elastin and matrix metalloproteinase-1 and -9 (MMP-1, 9) in chronic actinic dermatitis in elderly patients and explore the pathogenesis of the disease.</p><p><b>METHODS</b>Twenty-three patients with chronic actinic dermatitis were examined for the expressions of fibrillin-1, elastin, MMP-1, and MMP-9 with immunohistochemistry in the skin lesions. Image analysis was carried out to measure MMP-1 and MMP-9 expressions semi-quantitatively.</p><p><b>RESULTS</b>In the skin lesions of patients with chronic actinic dermatitis, elastin expression was obviously reduced or absent in the papillary dermis. The elastic fibers were disorderly arranged in the reticular dermis with local aggregation in some regions. Obvious fibrillin-1 deposition was found in the reticular dermis. Increased expressions of MMP-1, but not that of MMP-9, was found in the skin lesions of the patients.</p><p><b>CONCLUSION</b>Elastin and fibrillin-1 deposition can be found in the skin lesions in patients with chronic actinic dermatitis, suggesting the association of increased MMP-1 expression with the elastic tissue degeneration in the lesions. MMP-9 does not exhibit an obvious association with the pathogenesis of chronic actinic dermatitis in elderly patients.</p>

Two gene mutations in fibrillin 1 of Marfan syndrome / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To detect novel mutations in the fibrillin 1 (FBN1) and transforming growth factor beta receptor type II (TGFBR2) genes by screening the genes from 14 patients with Marfan syndrome.</p><p><b>METHODS</b>Denaturing high performance liquid chromatography (DHPLC) was introduced to screen for FBN1 and TGFBR2 mutations exon-by-exon. The DNA amplification fragments which DHPLC elution profiles showed different from the corresponding normal elution profile were sequenced to identify the positions and types of mutations. Restriction fragment length polymorphism (RFLP) was employed to further prove the mutations when needed.</p><p><b>RESULTS</b>Two gene mutations of the FBN1 were found in the patients with Marfan syndrome. They were a novel substitutional mutation (Intron29 +4A > T) of FBN1 and a recurrent nonsense mutation (8080C >T) of FBN1.</p><p><b>CONCLUSION</b>Intron29 +4A > T and 8080C > T of FBN1 are possibly the pathogenesis of the MFS patients.</p>

Two novel mutations in fibrillin-1 gene of Marfan syndrome / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To detect novel mutations in the fibrillin-1(FBN1) gene by screening the gene from 9 patients with Marfan syndrome (MFS).</p><p><b>METHODS</b>Denaturing high-performance liquid chromatography (DHPLC) was used to screen for FBN1 mutation exon by exon. The DNA amplification fragments of which the DHPLC elution profiles showed difference in comparison with the corresponding normal elution profile were sequenced to identify the position and nature of mutation. The detected mutations were further proved by allele specific PCR or restriction fragment length polymorphism.</p><p><b>RESULTS</b>Two novel FBN1 gene mutations were found and identified in two Marfan patients respectively, one of which was a small insertion in exon 34 at nucleotide 4307-4308 (4307insTCGT) and the other a missense mutation in exon 43 at nucleotide 5309 (5309G>A).</p><p><b>CONCLUSION</b>The findings suggested that the frameshift mutation (4307insTCGT) and point mutation (5309G>A) caused the corresponding patients to have MFS.</p>

Fibrillin-1 gene mutation in Chinese patients with Marfan syndrome and its gene diagnosis by haplotype analysis / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze fibrillin-1 (FBN(1)) gene mutation in Chinese patients with Marfan syndrome(MFS) and to make a gene diagnosis by haplotype analysis for MFS.</p><p><b>METHODS</b>Nine MFS families were analysed with single strand conformation polymorphism(SSCP) and DNA sequencing. With the use of four primers designed in the flanking sequences of each short-sequence tandem-repeat region in FBN(1) gene, the haplotype-segregation analysis for MFS(B) was performed.</p><p><b>RESULTS</b>In MFS(A)II(1), PCR-SSCP detected SSCP band alterations in exon 25 of FBN(1) gene; direct sequencing showed a small 13bp deletion, the deleted sequence being gcctctgcaccca at base 3243-3456 of cDNA. This mutation caused a frame-shift which was never seen in any unaffected members of the family, and it was a heterozygous mutation; neither of them was identified in 100 chromosomes from 50 normal control individuals. Haplotype-segregation analysis suggested that the disease was passed from Subject I(2) to Subject II(2), Subject II(3), Subject II(5) with the same allele in MFS B family, the proband's daughter also inherited the allele. These data indicated that MFS(B) family was linked to FBN(1) gene, the proband's daughter was an asymptomatic patient.</p><p><b>CONCLUSION</b>The combination of mutation analysis and haplotype analysis can provide more evidence for gene diagnosis.</p>