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Purpose To screen mutations in the fibrillin-1 (FBN1) gene in a Chinese family with autosomal dominant Marfan syndrome (MFS). Methods Patients and unaffected family members were given ophthalmic, cardiovascular, and physical examinations with a 5-year follow-up. Genomic DNA was extracted from the leukocytes of venous blood from all patients and their relatives. The entire coding region of the FBN1gene was screened with an ABI 9700 GeneAmp PCR System. The mutation identified was screened in 100 healthy and ethnically unrelated Chinese individuals. Results Mutation screening in FBN1 identified a T>G transition at position c.1786 in exon 14, leading to substitution of cysteine for glycine at codon 596 (C596G) in this four-generation Chinese family. The C596G mutation was associated with the disease phenotypes in all six patients but not found in 14 unaffected family members or the 100 ethnically unrelated and healthy controls. Conclusions A C596G mutation in FBN1 was identified in a Chinese family with MFS. Our results expand the spectrum of FBN1 mutations and contribute to the understanding of the role of FBN1 in the pathogenesis of Marfan syndrome.

Purpose To identify the spectrum and frequency of five candidate genes in Chinese patients with congenital ectopia lentis (EL). Methods Forty consecutive and unrelated congenital probands with EL were collected and underwent ocular, skeletal, and cardiovascular examinations. Sanger sequencing was used to analyze all of the coding and adjacent regions of five candidate genes: FBN1, ADAMTS10, ADAMTSL4, TGFBR2, and CBS. Mutation analysis was performed to evaluate the pathogenic variants and to identify the cause of congenital EL. Results The FBN1 gene screen revealed 25 pathogenic variants in 34 of the 40 families with congenital EL, including three novel (c.1955G>T, c.2222delA, and c.4381T>C) and 22 known mutations. The ADAMTSL10 gene screen revealed a compound heterozygous variant (c.1586G>A and c.2485T>A) in a family with Weill-Marchesani syndrome (WMS). In the remaining five probands, no pathogenic variant was detected in any of the five screened genes. Conclusions In this study, we identified three novel and 22 known mutations in FBN1 in 34 of 40 EL families. The results expand the mutation spectrum of the FBN1 gene and suggest that FBN1 mutations may be the major cause of congenital EL in Chinese patients.

Purpose To identify genetic defects in a Chinese family with ectopia lentis (EL) and varicose great saphenous vein (GSV) and to analyze the correlations between phenotype and genotype. Methods Twenty-two (12 affected subjects and ten unaffected subjects) among 53 members of a Chinese family underwent complete physical, ophthalmic, and cardiovascular examinations. Genomic DNA was extracted from the leukocytes in the subjects’ peripheral blood. A minimum interval was achieved with linkage study and haplotype analysis. All 65 exons and the flanking intronic regions of fibrillin-1 (FBN1) were amplified with PCR and screened for mutations with direct Sanger sequencing. Molecular modeling was analyzed in an in silico study. Results The linkage study showed a strong cosegregation signal on chromosome 15. The non-parametric linkage analysis yielded a maximum score of 29.1(pA, p.1310G>S in exon 31, was identified in FBN1 and cosegregated well in the family. We applied molecular modeling to show the effect of this mutation on the fibrillin-1 structure. The mutation significantly distorts the calcium coordination, decreases the binding of the calcium ion in that motif, and affects the local calcium-binding epidermal growth factor (cbEGF) interface that depends on Ca binding. Conclusions FBN1-associated fibrillinopathies are a group of diseases with dynamic phenotype changes. Novel mutation p.1310G>S was first reported to cause Marfan syndrome (MFS). Our results expand the mutation spectrum in FBN1 and enhance our knowledge of genotype–phenotype correlations underlying FBN1 mutations.

Purpose To identify the causative mutations in two Chinese families with autosomal dominant Marfan syndrome and to describe the associated phenotypes. Methods Complete physical, ophthalmic, and cardiovascular examinations were given to the patients and unaffected individuals in the two families. Exclusive linkage mapping was performed for transforming growth factor beta receptor II (TGFBR2) and fibrillin-1 (FBN1) loci in both families. The entire coding region and flanking splice sites of the FBN1 gene were screened for mutations in the two families with Sanger sequencing. The potential mutations of FBN1 were tested in 100 normal controls. Results Lens dislocation was observed in two out of ten patients in the MF1 family and all patients in the MF2 family. However, the MF1 family displayed more severe cardiovascular and skeletal system involvement compared with the MF2 family. The transforming growth factor beta receptor II locus was excluded in both families by linkage analysis. A maximum multipoint lod score score of 2.83 was obtained for marker D15S992 (located in the FBN1 gene) in the MF1 family and 1.51 for the same marker in the MF2 family. Two novel mutations of FBN1, p.C271* and p.C637Y, were identified in the MF1 and MF2 families, respectively. Conclusions Genotype-phenotype correlations in this study indicate that nonsense mutations of FBN1 may correlate with relatively severe systemic phenotypes when compared with cysteine substitutions, the most common type of FBN1 mutations. Genetic diagnosis for patients with Marfan syndrome would help with genetic counseling, clinical intervention, and prognosis.

Purpose To identify the mutation in the fibrillin-1 gene (FBN1) in a Chinese family with ectopia lentis (EL) and to predict the structural and functional consequences of the mutation. Methods Patients and family members were given complete physical, ophthalmic, and cardiovascular examinations. Genomic DNA was extracted from leukocytes of venous blood of three affected and three unaffected individuals in the family, and 100 healthy controls. All 65 coding exons and their flanking intronic boundaries of FBN1 were amplified in the proband by polymerase chain reaction, followed by direct sequencing. The mutation identified in the proband was screened for in other family members and 100 healthy controls by direct sequencing. Protein conservation analysis was performed in seven species using an online ClustalW tool. Protein structure was modeled based on the Protein data bank and mutated in PyMOL 1.1r1 to predict the structural and functional consequences of the mutation. Results A heterozygous c.2262A>G change in exon 18 of FBN1 was detected in the proband, which resulted in the substitution of tyrosine by cysteine at codon 754 (p.Y754C). This mutation was also present in the affected family members, but absent in other unaffected family members and 100 healthy controls. The mutant residue, located in the calcium binding epidermal growth factor-like7 domain, was highly conserved among mammalian species. The mutation could probably affect the disulfide bond formation of the domain and calcium binding of the adjacent domain, which would induce a critical functional change of the domain itself and neighboring domains. Conclusions We indentified a p.Y754C mutation in FBN1, which is the causative mutation for EL in this family. This missense mutation introduced an additional cysteine residue by substitution of a highly conserved tyrosine residue within the cbEGF-like7 module.

Purpose To identify the molecular defects in the fibrillin-1 gene (FBN1) in two Chinese families with ectopia lentis (EL) and marfanoid habitus. Methods Five patients and eight non-carriers in the two families underwent complete physical, ophthalmic, and cardiovascular examinations. Genomic DNA was extracted from leukocytes of venous blood of these individuals in the families as well as 100 healthy normal controls. Polymerase chain reaction (PCR) amplification and direct sequencing of all 65 coding exons of FBN1 were analyzed. The functional consequences of the mutations were analyzed with various genomic resources. Results Two novel mutations of FBN1 were identified in our study. One is a splice defect in intron 17 (IVS 17–1G>T) adjacent to exon 18. The other is c.6182G>T in exon 50, which results in the substitution of cysteine by phenylalanine at codon 2,061 (p. C2061F). We provided strong evidences that the splice mutation would potentially lead to the skipping of exons after intron 17 and that the missense mutation at codon 2,061 (p. C2061F) would destroy a disulfide bond. Conclusions We detected two novel mutations in FBN1. Our results expand the mutation spectrum of FBN1 and help in the study of the molecular pathogenesis of Marfan syndrome and Marfan-related disorders.

Purpose Screening of mutations in the fibrillin-1 (FBN1) gene in a Chinese family with autosomal dominant Marfan syndrome (MFS). Methods It has been reported that FBN1 mutations account for approximately 90% of Autosomal Dominant MFS. FBN1 mutations were analyzed in a Chinese family of 36 members including 13 MFS patients. The genomic DNAs from blood leukocytes of the patients and their relatives were isolated and the entire coding region of FBN1 was amplified by PCR. The sequence of FBN1 was dertermined with an ABI 3100 Genetic Analyzer. Results A previously unreported the missense mutation G214S (caused by a 640 A→G heterozygous change) in FBN1 was identified in the Chinese family. The mutation was associated with the disease phenotype in patients, but not detected in their relatives or in the 100 normal controls. Conclusions This is the first report of molecular characterization of FBN1 in the MFS family of Chinese origin. Our results expand the spectrum of FBN1 mutations causing MFS and further confirm the role of FBN1 in the pathogenesis of MFS. Direct sequencing of the mutation in FBN1 may be used for diagnosis of MFS.

Purpose Transforming growth factor beta receptor II (TGFBR2) gene mutations are associated with Marfan syndrome; however, the relationship between the mutations and clinical phenotypes are not clear. Methods Genomic DNA from peripheral blood leukocytes of a Chinese proband with Marfan syndrome, five of the proband’s relatives, and 100 unrelated Chinese control subjects were isolated and screened for fibrillin-1 (FBN1) and TGFBR2 gene mutations by direct sequencing, and a genotype-phenotype study was performed following a review of the literature on TGFBR2 mutations in the search area. Also, the structure of TGFBR2 protein before and after gene mutation was analyzed. Results The results identified a novel missense TGFBR2 mutation p.V453E (c.1358T>A) in the proband and two relatives that was located in the F-helix in the kinase domain of TGFBR2. No such genetic change was observed in the unrelated controls. No FBN1 mutation was detected in any of the subjects. Genotype-phenotype analyses indicated that F-helix mutations are related to type 2 Marfan syndrome and Loeys-Dietz syndrome, and these mutations can lead to severe cardiovascular (93.8%) and skeletal (81.3%) lesions and minor ocular lesions (25%). Losartan treatment can slow-down the progression of aortic lesions. Conclusions The findings extend the mutation spectrum of Marfan syndrome, and that mutations at the F-helix in the kinase domain of TGFBR2 may be associated with the development of severe cardiovascular and skeletal lesions and minor ocular lesions. These findings have implications for genetic testing, diagnosis, and treatment in individuals with transforming growth factor beta (TGF-β) signaling-related disorders.

Purpose To identify the genetic defect in an autosomal dominant isolated ectopia lentis (EL) family. Methods Detailed family history and clinical data were collected from the family including sixteen patients with isolated EL. Blood samples of nine patients, one normal person and two unknown children’s were collected. Genomic DNA was extracted from leukocytes of peripheral blood. Genotyping was performed by microsatellite markers and logarithm-of-odds (LOD) scores were calculated using the LINKAGE Programs. Mutation screening in the candidate gene, fibrillin-1 (FBN1), was performed by direct sequencing. Results Linkage to the FBN1 locus is verified. Mutation screening in FBN1 identified a C>T transition at nucleotide position c.2920. This nucleotide change results in the cysteine substitution for highly conserved arginine at codon 974 (p.R974C). This mutation is identified in all affected individuals but is not found in 50 control healthy people. Conclusions A novel mutation of FBN1 results in an arginine to cysteine residue (p.R974C) substitution, which is responsible for the patients with isolated EL in this Chinese family.

Purpose To identify the genetic defect in a Chinese family with autosomal dominant inherited ectopia lentis. Methods twenty-one family members, including seven patients underwent general physical and fully ophthalmic examinations. Genomic DNA was extracted from leukocytes of venous blood of these individuals in the family. Polymerase chain reaction (PCR) amplification and direct sequencing of all 65 coding exons of the fibrillin-1 gene (FBN1) were analyzed. Results Mutation screening in FBN1 identified a T>C transition at nucleotide position c,1759 leading to substitution of Cysteine for Arginine at codon 587 (C587R). This nucleotide substitution was not seen in any unaffected member of the family. Conclusions We detected a novel mutation in FBN1. Our result expands the mutation spectrum of FBN1 and help in the study of the molecular pathogenesis of Marfan syndrome and Marfan-related diseases.

Purpose To identify the mutation in the fibrillin-1 gene (FBN1) in a Chinese family with Marfan syndrome (MFS). Methods Patients and family members were given complete physical, ophthalmic, and cardiovascular examinations. Genomic DNA was extracted from leukocytes of venous blood of six individuals in the family and 170 healthy Chinese individuals. All of the 65 coding exons and their flanking intronic boundaries of FBN1 were amplified in the proband by polymerase chain reaction and followed by direct sequencing. The mutation identified in the proband was screened in the other family members and the 170 healthy Chinese individuals by direct sequencing. Protein conservation analysis was performed in six species using an online ClustalW tool. Protein structure was modeled based on the Protein data bank and mutated in DeepView v4.0.1 to predict the functional consequences of the mutation. Results A novel heterozygous c.3703T>C change in exon 29 of FBN1 was detected in the proband, which resulted in the substitution of serine by proline at codon 1235 (p.S1235P). This mutation was also present in two family members but absent in the other, unaffected family members and the 170 healthy Chinese individuals. The mutant residue located in the calcium binding epidermal growth factor-like#15 domain is highly conserved among mammalian species and could probably induce conformation change of the domain. Conclusions We indentified a novel p.S1235P mutation in FBN1, which is the causative mutation for MFS in this family. Our result expands the mutation spectrum of FBN1 and contributes to the study of the molecular pathogenesis of Marfan syndrome.

Purpose The genetic component underlying variation in central corneal thickness (CCT) in the normal population remains largely unknown. As CCT is an identified risk factor for open-angle glaucoma, understanding the genes involved in CCT determination could improve our understanding of the mechanisms involved in this association. Methods To identify novel CCT genes, we selected eight different candidates based on a range of criteria. These included; aquaporin 1 (AQ1), aquaporin 5 (AQ5), decorin (DCN), fibrillin-1 (FBN1), keratocan (KERA), lumican (LUM), osteoglycin (OGN), and paired box 6 (PAX6). Tagging single nucleotide polymorphisms (SNPs) selected from the HapMap database were genotyped to cover the majority of genetic variation within each gene. Each SNP was screened in a large, population-based cohort from Australia and both single SNP and haplotype analyses were undertaken. Results Two SNPs were found to be nominally associated with CCT, rs17352842 from FBN1 (p=0.02) and rs3026398 from PAX6 (p=0.02), although neither of these p values survived correction for multiple testing. Haplotype analysis revealed one haplotype within FBN1 (corrected p=0.048) and two haplotypes within PAX6 (strongest corrected p=0.006) associated with CCT. No other SNPs or haplotypes from the remaining genes showed any significant correlation with CCT. Conclusions Results from this study suggest that FBN1 and PAX6 are potentially involved in determining CCT. This is the first published study to investigate these genes for association with normal CCT variation.

Purpose To describe the clinical and genetic findings in one Chinese family with late-onset bilateral lens dislocation and secondary glaucoma. Methods One family including three affected members and 16 unaffected family members was examined clinically. After informed consent was obtained, genomic DNA was extracted from venous blood of all participants. Linkage analysis was performed with two microsatellite markers around the fibrillin-1 (FBN1) gene (D15S992 and D15S126). Mutation screening was performed using direct DNA sequence analysis and single strand conformation polymorphism (SSCP). Results Clinical examination and pedigree analysis revealed that four members in three generations were affected by late-onset lens dislocation and secondary glaucoma but had no signs of cardiovascular abnormality or abnormal skeletal features. By genotyping, the family showed the linkage to FBN1 on 15q21.1. After mutation screening analysis on 65 exons of FBN1, a novel heterozygous missense mutation, c.2860C>T (R954C), was detected. This mutation cosegregated with the disease phenotype in the family and was not found in 100 normal controls. Conclusions Late-onset isolated ectopia lentis with secondary glaucoma is consistent with a novel mutation in FBN1. Our finding expands the spectrum of FBN1 mutations and is useful for further genetic consultation and genetic diagnosis.

To identify mutations in the fibrillin-1 gene (FBN1) and provide further information about genotype-phenotype correlations in Chinese patients with predominant ectopia lentis (EL) and marfanoid habitus.Patients from seven Chinese families underwent complete physical, ophthalmic, and cardiovascular examination. Genomic DNA was extracted from leukocytes of peripheral blood from the patients. The 65 exons and flanking intronic sequences of FBN1 were amplified by polymerase chain reaction (PCR) and screened for mutation by direct DNA sequencing.Three novel mutations, c.203GT in exon 2, c.502TC in exon 5, and c.2096GC in exon 16 as well as four known mutations, c.364CT in exon 4, c.1633CT in exon 13, c.1879CT in exon 15, and c.4588CT in exon37, were identified in FBN1.We identified three novel mutations and four known mutations in FBN1 and found cysteine substitution highly related to EL. These results expand the mutation spectrum in FBN1 and enrich our knowledge of genotype-phenotype correlations due to FBN1 mutations. To our knowledge, this is the first report of cysteine residue loss in the unique NH2-terminal domain of fibrillin-1.

Ectopia lentis (EL) and Marfan syndrome (MFS) are considered two distinct clinical entities. We performed genetic and clinical studies to investigate whether EL is actually distinct from MFS or if it is a mild phenotypic expression of it.Seven patients with EL were followed for 5-10 years. Mutation screening analysis of the 65 exons of FBN1 was performed by polymerase chain reaction (PCR) amplification of genomic DNA, denaturing high pressure liquid chromatography analysis, and direct sequencing of heteroduplexes.Yearly examinations during the 10 years of follow-up allowed the detection of a late onset of dural ectasia in six out of seven patients (age range: 32-64 years versus 8-55 years in MFS previously reported). We also detected the onset of mild thoracic aortic dilatation in a sporadic case (age 45). Six out of seven index cases of EL turned out to be mild forms of Marfan syndrome with possible late cardiovascular involvement as detected in one case. Four novel missense mutations and one known splicing mutation were detected in five out of seven (71%) patients. Their localization confirmed the presence of a first hot spot within exons 1-15 and suggested the presence of a second one between exons 31-39.The presence of a second major criterion in six EL patients shifted the clinical diagnosis from EL to MFS. These data demonstrate that some cases, which are initially diagnosed as EL, turn out to be mild Marfan patients. A clinical cardiovascular follow-up is therefore highly recommended for all EL patients since they may develop thoracic aortic aneurysm (TAA) or dissection later in life. Also magnetic resonance imaging (MRI) for dural ectasia (DE) should be performed in a complete follow up for a MFS diagnosis.

To identify the genetic defect in an autosomal dominant ectopia lentis (EL) family having 27 affected members in four generations.Detailed family history and clinical data were recorded for 48 family members including 24 persons with isolated ectopia lentis. Candidate gene regions at 5q and 15q known to be linked with ectopia lentis were analyzed using fluorescent labeled microsatellite markers. Mutation screening in the candidate gene, fibrillin-1 (FBN1), at 15q was performed by bidirectional sequencing of the amplified products.A maximum LOD score of 5.74 at theta=0.0 was obtained with marker D15S1024 in close proximity to FBN1 at 15q21. Mutation screening in FBN1 identified a CT transition at nucleotide position c.718. This nucleotide change resulted in the substitution of highly conserved arginine by cysteine at codon 240 (R240C). This nucleotide substitution was not seen in any unaffected member of the family.We report a recurrent R240C mutation in FBN1 in an autosomal dominant ectopia lentis family. This mutation has previously been reported in a family with isolated ectopia lentis, in another family with ectopia lentis and involvement of the skeleton and integument, and in one person with classic Marfan syndrome. This is the largest family with isolated ectopia lentis reported to date. The results of the present study provide convincing evidence for a correlation of R240C and isolated ectopia lentis. In addition, this is the first report of molecular characterization in an ectopia lentis family of Indian origin.

To describe the clinical, ocular, and genetic findings in multiple members of a family with early-onset and bilateral lens dislocation, clinical corneal guttae, and glaucoma.All family members underwent complete physical and ophthalmic examinations. After informed consent was given, DNA was obtained from eleven family members, eight of whom were affected. Three polymorphic markers near the fibrillin 1 (FBN1) locus were genotyped and the results analyzed using the VITESSE program. Amplification of the 65 exons and flanking intronic sequences of FBN1 was performed using polymerase chain reaction (PCR), followed by conformation sensitive gel electrophoresis (CSGE). Then, all fragments with mobility variations were sequenced.Pedigree analysis revealed a three generation family with eight of eleven individuals affected by early onset lens dislocation, high myopia, typical facies, frontal bossing, flexion contractures, proximal interphalangeal (PIP) joint thickening, clinical corneal guttae, and glaucoma. Genetic linkage analysis using polymorphic markers near FBN1 demonstrated an LOD score of 1.78 (maximum possible LOD score 1.78). Conformation sequence gel electrophoresis analysis suggested a sequence variation in exon 3. Sequencing revealed a C965G substitution, resulting in an S322C coding change. This sequence variant segregated with affection status and was not identified in 154 control chromosomes.This syndrome is consistent with a novel mutation in the FBN1 gene. FBN1 mutations have been previously described as causative for Marfan syndrome. The early-onset of complete lens dislocation, progressive corneal guttae, and glaucoma is unusual for Marfan syndrome. This study expands the Marfan phenotype and demonstrates a possible link between guttae, glaucoma, and fibrillin 1 disorders.