TGFBI Research Articles

Repair of the TGFBI gene in human corneal keratocytes derived from a granular corneal dystrophy patient via CRISPR/Cas9-induced homology-directed repair

Granular corneal dystrophy (GCD) is an autosomal dominant hereditary disease in which multiple discrete and irregularly shaped granular opacities are deposited in the corneal stroma. GCD is caused by a point mutation in the transforming growth factor-β-induced (TGFBI) gene, located on chromosome 5q31. Here, we report the first successful application of CRISPR-Cas9-mediated genome editing for the correction of a TGFBI mutation in GCD patient-derived primary corneal keratocytes via homology-directed repair (HDR). To correct genetic defects in GCD patient cells, we designed a disease-specific guide RNA (gRNA) targeting the R124H mutation of TGFBI, which causes GCD type 2 (GCD2). An R124H mutation in primary human corneal keratocytes derived from a GCD2 patient was corrected by delivering a CRISPR plasmid expressing Cas9/gRNA and a single-stranded oligodeoxynucleotide HDR donor template in vitro. The gene correction efficiency was 20.6% in heterozygous cells and 41.3% in homozygous cells. No off-target effects were detected. These results reveal a new therapeutic strategy for GCD2; this method may also be applicable to other heredity corneal diseases.

Post-LASIK exacerbation of granular corneal dystrophy type 2 in members of a chinese family

PurposeThe post-LASIK exacerbation of corneal dystrophy, otherwise asymptomatic, is almost exclusively associated with the TGFBI gene mutations at codon 124 in exon 4 and codon 555 in exon 12. It is our intention to demonstrate that the pre-operative genetic screening for TGFBI mutations should be mandatory for refractive surgery candidates.Patients and MethodsIn this study, we reviewed the proband’s post-LASIK slit-lamp and in vivo confocal microscopy images and genetic testing results, and performed genetic testing on eleven additional members of the family to investigate the penetrance of corneal dystrophy in asymptomatic members who carry the mutation.ResultsThe proband demonstrated a post-LASIK exacerbation of Granular Corneal Dystrophy type 2 (GCD2), identified as a TGFBI R124H mutation. Three of the 11 family members tested positive for the same R124H mutation as the proband.ConclusionThe lesson learned from this case is that the genetic screening of TGFBI mutations must be incorporated into the pre-operative screening procedures to prevent exacerbation and recurrence, which eventually could lead to the need for a corneal transplant.

Proteomic profiling of TGFBI-null mouse corneas reveals only minor changes in matrix composition supportive of TGFBI knockdown as therapy against TGFBI-linked corneal dystrophies.

TGFBIp is a constituent of the extracellular matrix in many human tissues including the cornea, where it is one of the most abundant proteins expressed. TGFBIp interacts with Type I, II, IV, VI, and XII collagens as well as several members of the integrin family, suggesting it plays an important role in maintaining structural integrity and possibly corneal transparency as well. Significantly, more than 60 point mutations within the TGFBI gene have been reported to result in aberrant TGFBIp folding and aggregation in the cornea, resulting in severe visual impairment and blindness. Several studies have focused on targeting TGFBIp in the cornea as a therapeutic approach to treat TGFBI-linked corneal dystrophies, but the effect of this approach on corneal homeostasis and matrix integrity remained unknown. In the current study, we evaluated the histological and proteomic profiles of corneas from TGFBI-deficient mice as well as potential redundant functions of the paralogous protein POSTN. The absence of TGFBIp in mouse corneas did not grossly affect the collagen scaffold, and POSTN is unable to compensate for loss of TGFBIp. Proteomic comparison of wild-type and TGFBI-/- mice revealed 11 proteins were differentially regulated, including Type VI and XII collagens. However, as these alterations did not manifest at the macroscopic and behavioral levels, these data support partial or complete TGFBI knockdown as a potential therapy against TGFBI-linked corneal dystrophies. Lastly, in situ hybridization verified TGFBI mRNA in the epithelial cells but not in other cell types, supportive of a therapy directed specifically at this lineage.

Genetic testing for corneal dystrophies and other corneal Mendelian diseases

Abstract We studied the scientific literature and disease guidelines in order to summarize the clinical utility of the genetic test for corneal dystrophies and other Mendelian corneal diseases (CDs). CDs are mostly inherited in an autosomal dominant manner (autosomal recessive inheritance is rare). The overall prevalence is currently unknown. CDs are caused by mutations in the AGBL1, CHST6, COL8A2, DCN, GSN, KRT12, KRT3, NLRP1, PAX6, PIKFYVE, PRDM5, SLC4A11, TACSTD2, TCF4, TGFBI, UBIAD1, VSX1, ZEB1, and ZNF469 genes. Clinical diagnosis is based on clinical findings, ophthalmological examination, confocal microscopy and slit-lamp biomicroscopy. The genetic test is useful for confirming diagnosis and for differential diagnosis, couple risk assessment and access to clinical trials.

Analysis of TGFBI gene mutation in a Chinese family affected with Reis-Bucklers corneal dystrophy

To analyze the clinical features and TGFBI gene mutation in a Chinese family affected with Reis-Bucklers corneal dystrophy. Genomic DNA was extracted from 53 members including 9 patients from the family. The 17 exons and splice region of introns of the TGFBI gene were amplified by PCR and directly sequenced. All family members were subjected to ophthalmologic examination. A heterozygous mutation (R124L) was found in exon 4 of the TGFBI gene among all patients from the family. The same mutation was not found among unaffected family members. The inheritance pattern of the family was identified as autosomal dominant, and the Reis-Bucklers corneal dystrophy in the family was diagnosed as the geographic type. The R124L mutation of the TGFBI gene probably underlies the pathogenesis of Reis-Bucklers corneal dystrophy in this Chinese family. Molecular genetic approach is useful for the proper diagnosis of this type of corneal dystrophy.

Transforming growth factor β induced mutation-associated phenotype in a Chinese family exhibiting lattice corneal dystrophy.

Lattice corneal dystrophy type I (LCDI) is associated with a large number of missense mutations in the transforming growth factor β induced (TGFBI) gene. The aim of the present study was to analyze TGFBI mutation in a Chinese family with LCDI, and to describe the clinical features and phenotype-genotype correlation within this family. Three generations of this family with LCDI were enrolled in the current study. Complete ophthalmic examinations were performed on all family members and mutation screenings of the coding regions of TGFBI were analyzed using a direct sequencing method. All family members underwent slit-lamp examination, and two patients and one of normal members in the family were evaluated by laser scanning in vivo confocal microscopy. A single heterozygous c.370C>T (p.R124C) mutation was identified in exon 4 of the TGFBI gene in five affected individuals, but not in the other family members and 400 normal control subjects. The affected members exhibited similar clinical features of LCDI, except that patient III:5 presented with mild symptoms. Confocal microscopy in vivo examination demonstrated that the proband (II:2) and his affected niece (III:4) had disruptions in multiple corneal layers, including the basal epithelial cells, stroma cells and Bowman's membrane. Thus, the R124C mutation in the TGFBI gene was identified in a Chinese family with LCDI. These results characterized the clinical features and revealed a genotype-associated phenotype in this family, which may contribute to understanding the pathogenesis of LCDI.

Proteomic Analysis of Amyloid Corneal Aggregates from TGFBI-H626R Lattice Corneal Dystrophy Patient Implicates Serine-Protease HTRA1 in Mutation-Specific Pathogenesis of TGFBIp.

TGFBI-associated corneal dystrophies are inherited disorders caused by TGFBI gene variants that promote deposition of mutant protein (TGFBIp) as insoluble aggregates in the cornea. Depending on the type and position of amino acid substitution, the aggregates may be amyloid fibrillar, amorphous globular or both, but the molecular mechanisms that drive these different patterns of aggregation are not fully understood. In the current study, we report the protein composition of amyloid corneal aggregates from lattice corneal dystrophy patients of Asian origin with H626R and R124C mutation and compared it with healthy corneal tissues via LC-MS/MS. We identified several amyloidogenic, nonfibrillar amyloid associated proteins and TGFBIp as the major components of the deposits. Our data indicates that apolipoprotein A-IV, apolipoprotein E, and serine protease HTRA1 were significantly enriched in patient deposits compared to healthy controls. HTRA1 was also found to be 7-fold enriched in the amyloid deposits of patients compared to the controls. Peptides sequences (G511DNRFSMLVAAIQSAGLTETLNR533 and Y571HIGDEILVSGGIGALVR588) derived from the fourth FAS-1 domain of TGFBIp were enriched in the corneal aggregates in a mutation-specific manner. Biophysical studies of these two enriched sequences revealed high propensity to form amyloid fibrils under physiological conditions. Our data suggests a possible proteolytic processing mechanism of mutant TGFBIp by HTRA1 and peptides generated by mutant protein may form the β-amyloid core of corneal aggregates in dystrophic patients.

Mutation analysis of TGFBI and KRT12 in a case of concomitant keratoconus and granular corneal dystrophy.

This study is to summarize the concurrent keratoconus (KC) and granular corneal dystrophy (GCD) phenotype and identify the underlying genetic cause in a 23-year-old male patient. A detailed family history and clinical data from the patient and his parents were collected by ophthalmologic examination. The candidate genes were captured and sequenced by targeted next-generation sequencing, and the results were confirmed by Sanger sequencing. The proband was clinically diagnosed as a case of concurrent KC and GCD, which is a very rare presentation. His father and grandmother were diagnosed as GCD in both eyes. There was no character of KC in his father's and grandmother's eyes. A heterozygous TGFBI mutation in exon 4 (c.370G>A) was identified in the proband, which was predicted to generate a missense mutation (p.R124H). The mutation also existed in his father and grandmother. A heterozygous KRT12 mutation in exon 8 (c.1456-1457ins GTA) was identified in the proband, which was predicted to generate an insert mutation and created a premature termination codon. The mutation did not exist in his father and grandmother. The two mutations did not exist in his mother and 200 unrelated normal controls. KC can co-exist with GCD. The missense mutation (c.370G>A) in the TGFBI gene and insert mutation (c.1456-1457ins GAT) in the KRT12 gene were identified in a 23-year-old male patient with concurrent KC and GCD.

TGFBI Gene Mutation Analysis of Clinically Diagnosed Granular Corneal Dystrophy Patients Prior to PTK: A Pilot Study from Eastern China

This study investigated the TGFBI gene mutation types in outpatients clinically diagnosed with granular corneal dystrophy (GCD) prior to phototherapeutic keratectomy (PTK), also calculated the mutation rate of subjects with normal corneas, but positive family history. Clinical GCD outpatients and consanguineous family members were enrolled in this study. Among total 42 subjects: 24 patients from 23 unrelated families had typical signs of GCD on corneas; 5 patients from 5 unrelated families had atypical signs; 13 subjects from 11 unrelated families had no corneal signs but positive family history. Using Avellino gene test kit, the TGFBI mutation detection was performed on DNA samples from all subjects. 36 subjects were detected to carry heterozygous TGFBI gene mutations. Among 24 clinical GCD patients, the proportion of R124H, R555Q, R124L, R555W and R124C were 37.5%, 16.7%, 25.0%, 20.8% and 0%, respectively, and 2 patients had been diagnosed with GCD according to the opacities thriving after LASIK (R124H) and PRK (R555W). The mutation rate of 13 subjects having no signs but positive family history was 69.2%. R124H mutation is the most prominent mutation type among GCD outpatients in Eastern China. It is recommended to conduct gene detection for patients with positive family history prior to refractive surgeries.

TGFBI gene mutations analysis in Chinese families with corneal dystrophies

The aim of the present study was to examine the clinical features of three Chinese families with autosomal dominant corneal dystrophy (CD) and examine transforming growth factor‑β‑induced (TGFBI) gene mutations in these families. The TGFBI gene mutations were detected using direct sequencing of the whole coding regions and exon-intron boundaries of the TGFBI gene in the affected members from the three families with CD. The phenotypes of all affected individuals in the three families were observed via slit lamp examination. Sections of the cornea were used for biopsy following keratoplasty. Three types of TGFBI gene mutations, R124C, H626R and R124H, were detected in the patients from these three families. One family, with the R124C mutation, was diagnosed with lattice corneal dystrophy type 1, and the family with the H626R mutation was diagnosed with lattice corneal dystrophy type IIIB. The family with the R124H mutation was diagnosed with granular corneal dystrophy type2. The TGFBI gene mutations were considered underlying factors in the molecular mechanism underlying the pathogenesis of cornea dystrophy. Therefore, the detection of TGFBI gene mutations may be useful in the differential diagnosis of CD.

Two mutations in the transforming growth factor beta-induced gene associated with familial Lattice corneal dystrophy.

To report a phenotypic variant pedigree of lattice corneal dystrophy (LCD) associated with two mutations, R124C and A546D, in the transforming growth factor beta-induced gene (TGFBI). A detailed ocular examination was taken for all participants of a LCD family. Peripheral blood leukocytes from each participant were extracted to obtain the DNA. Polymerase chain reaction (PCR) of all seventeen exons of TGFBI gene was performed. The products were sequenced and analyzed. Histological examination was carried out after a penetrating keratoplasty from the right eye of proband. Genetic analysis showed that the proband and all 6 affected individuals harbored both a heterozygous CGC to TGC mutation at codon 124 and a heterozygous GCC to GAC mutation at codon 546 of TGFBI. None of the 100 control subjects and unaffected family members was positive for these two mutations. Ocular examination displayed multiple refractile lattice-like opacities in anterior stroma of the central cornea and small granular deposits in the peripheral cornea. The deposits were stained positively with Congo red indicating be amyloid in nature and situated mainly in the anterior and middle stroma. We observed a novel LCD family which carried two pathogenic mutations (R124C and A546D) in the TGFBI gene. The phenotypic features were apparently different from those associated with corresponding single mutations. The result reveals that although the definite mutation is the most important genetic cause of the disease, some different modifier alleles may influence the phenotype.

New histopathologic and ultrastructural findings in Reis-Bücklers corneal dystrophy caused by the Arg124Leu mutation of TGFBI gene.

BackgroundReis-Bücklers corneal dystrophy (RBCD) was consistently reported as a corneal dystrophy only affected Bowman’s layer and superficial corneal stroma, and superficial keratectomy was a recommendation surgery for treatment in literatures. The study reported new histopathological and ultrastructural findings in RBCD caused by the Arg124Leu mutation of transforming growth factor induced (TGFBI) gene in a four-generation Chinese pedigree.MethodsSubjects including eight patients and seven unaffected family members received slit-lamp biomicroscopy and photography. DNA was obtained from all subjects, and exons 4 and 11 to 14 of TGFBI gene were analyzed by polymerase chain reaction and the products were sequenced. Anterior segment optical coherence tomography (AS OCT) and in vivo confocal microscopy were conducted for ten eyes of five patients. Based on the results of AS OCT and in vivo confocal microscopy, deep anterior lamellar keratoplasty (DLKP) using cryopreserved donor cornea was applied for four eyes of four patients. Four lamellar dystrophic corneal buttons were studied by light and transmission electron microscopy, and TGFBI immunohistochemistry.ResultsEight patients had typical clinical manifestations of RBCD presenting recurrent painful corneal erosion starting in their early first decades, along with age-dependent progressive geographic corneal opacities. TGFBI sequencing revealed a heterozygous mutation, Arg124Leu in all eight patients. Anterior segment optical coherence tomography and in vivo confocal microscopy showed the dystrophic deposits involved not only in subepithelial and superficial stroma, but also in mid- or posterior stroma in four examined advanced eyes. Light microscopy showed Bowman’s layer was absent, replaced by abnormal deposits stain bright red with Masson’s trichrome. In superficial cornea, the deposits stacked and produced three to five continuous bands parallel to the corneal collagen lamellae. In mid- to posterior stroma, numerous granular or dot- like aggregates were heavily scattered, and most of them presented around the nuclei of stromal keratocytes. Transmission electron microscopy revealed the multiple electron-dense rod-shaped deposits aggregated and formed a characteristic pattern of three to five continuous bands in superficial cornea, which were similar to those seen under light microscopy. In mid- to posterior stroma, clusters of rod-shaped bodies were scattered extracellular or intracellular of the stromal keratocytes between the stromal lamellae suggesting the close relationship between mutated proteins and keratocyte.ConclusionsThe study offer evidences indicating DLKP is a viable treatment option for advanced RBCD to avoid recurrence, and the mutated TGFBIp in dystrophic corneas are of keratocytes origin.

Genetics in Keratoconus: where are we?

Keratoconus (KC) is a non-inflammatory thinning and protrusion of the cornea in which the cornea assumes a conical shape. Complex etiology of this condition at present remains an enigma. Although environmental factors have been involved in KC pathogenesis, strong underlining genetic susceptibility has been proven. The lack of consistent findings among early genetic studies suggested a heterogeneity and complex nature of the genetic contribution to the development of KC. Recently, genome-wide linkage studies (GWLS) and genome-wide association studies (GWAS) were undertaken. Next-generation sequencing (NGS)-based genomic screens are also currently being carried out. Application of these recently developed comprehensive genetic tools led to a much greater success and increased reproducibility of genetic findings in KC. Involvement of the LOX gene identified through GWLS has been confirmed in multiple cohorts of KC patients around the world. KC susceptibility region located at the 2q21.3 chromosomal region near the RAB3GAP1 gene identified through GWAS was independently replicated. Rare variants in the ZNF469 gene (mutated in corneal dystrophy Brittle Cornea Syndrome) and in the TGFBI gene (mutated in multiple corneal epithelial–stromal TGFBI dystrophies) have been repeatedly identified in familial and sporadic KC patients of different ethnicities. Additional comprehensive strategies using quantitative endophenotypes have been successfully employed to bring further understanding to the genetics of KC. Additional genetic determinants including the COL5A1 gene have been identified in the GWAS of KC-related trait central corneal thickness. These recent discoveries confirmed the importance of the endophenotype approach for studying complex genetic diseases such as KC and showed that different connective tissue disorders may have the same genetic determinants.

Identification of two novel mutations in the cornea-specific TGFBI gene causing unique phenotypes in patients with corneal dystrophies.

The purpose of this study was to report on two novel missense mutations of the cornea-specific TGFBI gene in one single patient and in two generations of a family diagnosed with unique corneal dystrophy (CD) phenotypes. Ophthalmologic examination, in several cases ocular coherence tomography of the anterior segment (AS-OCT), was performed in 21 affected patients and in two unaffected members of one affected family. Coding regions of the TGFBI gene were direct sequenced in all 23 individuals. The two novel mutations were verified by RFLP analysis. A novel mutation c.1640T>G (p.Phe574Cys) in exon 12 of the TGFBI gene was detected in one single patient with recurrent granular intrastromal deposits comparable to a type of granular dystrophy. In AS-OCT, the deposit pattern reached up to the Descemet's layer. A further novel mutation c.393G>T(p.Glu131Asp) in exon 4 of the TGFBI gene was detected in all three affected members of one family with superficial cloud- and honeycomb-like opacifications, comparable to a Schnyder corneal dystrophy. Two unaffected members did not carry this alteration. The two identified novel mutations add other two phenotypes in patients suffering from TGFBI-linked CD to those reported so far. In one case, clinical finding indicates a Schnyder corneal dystrophy-like phenotype due to its superficial crystalline shape, and in the second one, granular deposits who reach Descemet's layer indicate a granular CD subtype. Molecular genetic analysis may help to distinguish those subtypes and to decide for specific treatment in time of a wide variation of corneal surgical techniques.

βig-h3 Represses T-Cell Activation in Type 1 Diabetes.

βig-h3/TGF-βi is a secreted protein capable of binding to both extracellular matrix and cells. Human genetic studies recently revealed that in the tgfbi gene encoding for βig-h3, three single nucleotide polymorphisms were significantly associated with type 1 diabetes (T1D) risk. Pancreatic islets express βig-h3 in physiological conditions, but this expression is reduced in β-cell insult in T1D. Since the integrity of islets is destroyed by autoimmune T lymphocytes, we thought to investigate the impact of βig-h3 on T-cell activation. We show here that βig-h3 inhibits T-cell activation markers as well as cytotoxic molecule production as granzyme B and IFN-γ. Furthermore, βig-h3 inhibits early T-cell receptor signaling by repressing the activation of the early kinase protein Lck. Moreover, βig-h3-treated T cells are unable to induce T1D upon transfer in Rag2 knockout mice. Our study demonstrates for the first time that T-cell activation is modulated by βig-h3, an islet extracellular protein, in order to efficiently avoid autoimmune response.

A novel phenotype-genotype correlation with an Arg555Trp mutation of TGFBI gene in Thiel-Behnke corneal dystrophy in a Chinese pedigree.

BackgroundTo investigate the molecular defects in a four-generation Chinese pedigree affected with Thiel-Behnke corneal dystrophy (TBCD). And to further study the relationship between genetic mutation and clinical manifestations.MethodsIndividuals of the pedigree were recruited for extensive ophthalmic examinations. Histological studies of two corneal buttons obtained from lamellar keratoplasty were conducted. Peripheral blood was collected in EDTA for genomic DNA isolation from leukocytes of all affected and unaffected members. All 17 exons of the TGFBI gene were screened for mutations by polymerase chain reaction and direct DNA sequencing.ResultsClinical examinations revealed a typical pattern of honeycomb-like TBCD. Histopathology study demonstrated eosinophilic deposits that were congo-red-positive and did not stain with periodic acid Schiff or Masson’s trichrome. Genetic analysis disclosed a heterozygous p. Arg555Trp mutation resulted from a missense c. 1663C > T nucleotide change in exon 12 of TGFBI gene in all affected members. Morever, a second rare variant in exon 6 of the TGFBI gene (p. Arg257Trp) also cosegregated within this family and has been confirmed to be a single nucleotide polymorphism (SNP) not previously reported.ConclusionsThe p. Arg555Trp mutation of the TGFBI gene was associated with TBCD, which revealed a novel phenotype-genotype correlation within the mutational spectrum of phenotypically diverse corneal dystrophies.

Genotype and phenotype correlation of monogenic corneal dystrophies in population of central Poland

PurposeTo assess the genotype‐phenotype correspondence in monogenic corneal dystrophies caused by KRT,TGFBI and UBIAD1 genes mutation.Methods61 patients from 30 Polish families with clinically diagnosed epithelial and stromal corneal dystrophies participated in the study.Corneal phenotypes were assessed by slit lamp, AS‐OCT,and confocal microscopy in vivo. Genomic DNA was obtained from blood samples and respective exons (hot spots) were PCR amplified and sequenced on both strands.ResultsMolecular genetic testing revealed heterozygous missense p.E498V mutation (exon 7) of KRT3 in one family with Meesmann corneal dystrophy phenotype, p.R555W (exon 12) mutation in 19 patients diagnosed with granular type I dystrophy (GCD1). In two patients p.R124H mutation (GCD2, Avellino) was found. In three patients (2 families) heterozygous p.R124L (exon 4) mutation was identified and diagnosed as Reis‐Buecklers dystrophy. In two unrelated patient p.R555Q (exon 12) mutation typical for Thiel‐Behnke dystrophy was found. Heterozygous p.R124C (exon 4), p.T538R (exon 12) and p.H626R (exon 14) mutations were identified, respectively, in 10 patients diagnosed with lattice corneal dystrophy (LCD1). A novel p.L565P mutation was found in one family with late‐onset LCD.Among 18 idividuals (4 families) suffering from stromal Schnyder corneal dystrophy (SCD) molecular genetic testing revealed 3 different UBIAD1 gene mutations: p.N102S, p.D112N, p.T120R.ConclusionsThe genotype typical for monogenic corneal dystrophies caused by KRT and UBIAD1 genes mutation corresponds with its clinical phenotype. TGFBI is associated with phenotype heterogenity and in some cases only genetic tests may confirm the proper diagnosis.This indicates that a relatively straightforward molecular analysis can be a practical use in diagnosis of these conditions and associated genetic counseling.

Mutation Analysis of the TGFBI Gene in Consecutive Korean Patients With Corneal Dystrophies.

BackgroundMutations in the transforming growth factor β-induced gene (TGFBI) are major causes of genetic corneal dystrophies (CDs), which can be grouped into TGFBI CDs. Although a few studies have reported the clinical and genetic features of Korean patients with TGFBI CD, no data are available regarding the frequency and spectrum of TGFBI mutations in a consecutive series of Korean patients with clinically diagnosed CDs.MethodsPatients with any type of CD, who underwent both ophthalmologic examination and TGFBI gene analysis by Sanger sequencing at a tertiary care hospital in Seoul, Korea from 2006 to 2013, were enrolled in this study.ResultsAmong a total of 89 patients, 77 (86.5%) were diagnosed as having clinical TGFBI CD. Seventy-three out of 74 patients (98.6%) with granular CD type 2 (GCD2), had the p.R124H mutation. Of particular note, one patient with rapidly progressive CD had the p.R124H mutation as well as a novel nonsense variant with unknown clinical significance (p.A179*). In three patients with lattice CD type 1 (LCD1), one known mutation (p.R124C) and two novel variants (p.L569Q and p.T621P) in the TGFBI gene were identified.ConclusionsThis study provides epidemiological insight into CDs in a Korean population and reaffirms that GCD2 is the most common TGFBI CD phenotype and that p.R124H is the only mutation identified in patients with GCD2. In addition, we broaden the spectrum of TGFBI mutations by identifying two novel missense variants in patients with LCD1.

The role of TGFBI (βig-H3) in gastrointestinal tract tumorigenesis.

BackgroundTGFβ-induced (TGFBI/βig-H3) is a protein inducible by TGFβ1 and secreted by many types of cells. It binds to collagen, forms part of the extracellular matrix (ECM), and interacts with integrins on cell surfaces. In this study, we investigated the role of TGFBI in tumorigenesis and the underlying mechanisms.MethodsPatient serum TGFBI levels were determined by ELISA. TGFBI transgenic and gene knockout mice and TGFBI-overexpressing liver cells were used for mechanistic studies.ResultsWe demonstrated that patients with cholangiocarcinomas, hepatic carcinomas or gastric carcinomas presented significantly elevated serum TGFBI levels, and the excess TGFBI was derived from the tumor masses. TGFBI overexpression in mice resulted in increased incidence of spontaneous tumors and N,N-diethylnitrosamine (DEN)-induced liver tumor nodules, compared to that in wild type (WT) mice, while TGFBI knockout mice were comparable to WT controls in these 2 aspects. TGFBI promoted the survival of Aml-12 liver cells with DNA damage after irradiation, and augmented their post-irradiation proliferation. It activated the FAK/AKT/AKT1S1/PRS6/EIF4EBP pathway, which is known to modulate cell survival and proliferation.ConclusionsOur data suggest that TGFBI functions as a promoter of certain gastrointestinal tract cancers. It provides a survival advantage to cells with DNA damage. Over a long time span, this advantage could translate into increased tumor risks.

Analyses of TGFBI gene mutation spectrum in four Chinese families with corneal dystrophy

To identify the genetic mutation of TGFBI gene in four Chinese families with corneal dystrophy. The pedigrees were Reis-Bücklers corneal dystrophy (RBCD), Avellino corneal dystrophy (ACD), lattice corneal dystrophy type I(LCDI) and lattice corneal dystrophy type I/IIIA (LCDI/IIIA) (n = 1 each). Genomic DNA was extracted from leukocytes from 22 patients, 22 phenotypic normal family members and 100 normal controls from February 2010 to October 2012. And 17 exons of TGFBI gene were amplified by polymerase chain reaction and sequenced directly. The corneas were examined with slit-lamp biomicroscope and photographed. Mutations of TGFBI gene occurred in all 22 patients, including R124L (c.371G > T) in 14 patients with RBCD, R124H (c.371G > A) mutation in 1 patient with ACD, R124C (c.370C > T) mutation in 3 patients with LCDIand H626R (c.1877A > G) mutation in 4 patients with LCD I/IIIA. The mutations were absent in all participating unaffected family members and normal controls. TGFBI gene-linked corneal dystrophy has close genotype-phenotype relationship. And R124 is a mutant hotspot of TGFBI gene of corneal dystrophy.