TGIF1 Research Articles

Evaluation of CRISPR/Cas9 mediated TGIF gene editing to inhibit corneal fibrosis in vitro

Corneal wound healing is influenced by many factors including transcriptional co-repressors and co-activators. Interactions of co-activators and co-repressors with Smads influence mechanistic loop facilitating transcription of alpha-smooth muscle actin (α-SMA), a key profibrotic gene, in corneal repair. The role of a transcriptional repressor, 5′TG3′-interacting factor (TGIF), in the regulation of α-SMA and myofibroblast formation in the cornea was shown previously by our group. This study tested a hypothesis if TGIF1 gene editing via CRISPR/Cas9 can ease myofibroblast formation in the cornea using an in vitro model. Primary human corneal stromal fibroblasts (hCSFs) generated from donor corneas received gene-editing plasmid facilitating loss (CRISPR/Cas9 knockout) or gain (CRISPR activation) of TGIF function by UltraCruz transfection reagent. Phase-contrast microscopy, immunoblotting, immunocytochemistry and quantitative polymerase chain reaction (qPCR) were used to measure levels of myofibroblast profibrotic genes (α-SMA, fibronectin, Collagen-I, and Collagen-IV) in hCSFs lacking or overexpressing TGIF1 after growing them in± transforming growth factor beta1 (TGF-β1) under serum-free conditions. The CRISPR-assisted TGIF1 activation (gain of function) in hCSFs demonstrated significantly decreased myofibroblast formation and messenger ribonucleic acid (mRNA) and protein levels of profibrotic genes. Conversely, CRISPR/Cas9-assisted TGIF knockdown (loss of function) in hCSFs demonstrated no significant change in the levels of myofibroblast formation or profibrotic genes under similar conditions. These results suggest that TGIF gene-editing approach can be employed to modulate the transcriptional activity of α-SMA in controlling pathological and promoting physiological wound healing in an injured cornea.

E3 ubiquitin ligase FBXW7 balances airway cell fates

The airway epithelium is composed of multiple cell types each with designated roles. A stereotyped ratio of these cells is essential for proper airway function. Imbalance of airway cell types underlies many lung diseases, including chronic obstructive pulmonary disease (COPD) and asthma. While a number of signals and transcription factors have been implicated in airway cell specification, how cell numbers are coordinated, especially at the protein level is poorly understood. Here we show that in the mouse trachea which contain epithelial cell types similar to human airway, epithelium-specific inactivation of Fbxw7, which encodes an E3 ubiquitin ligase, led to reduced club and ciliated cells, increased goblet cells, and ectopic P63-negative, Keratin5-positive transitory basal cells in the luminal layer. The protein levels of FBXW7 targets including NOTCH1, KLF5 and TGIF were increased. Inactivation of either Notch1, Klf5 but not Tgif genes in the mutant background led to attenuation of selected aspects of the phenotypes, suggesting that FBXW7 acts through different targets to control different cell fates. These findings demonstrate that protein-level regulation by the ubiquitin proteasome system is critical for balancing airway cell fates.

A novel G26A variation in 5' half of TGIF1 gene associates with high myopia in ethnic Kashmiri population from India.

This study aims to look at novel variations in TGIF1 gene and explores their potential association with high myopia in an ethnic population from Kashmir (India). Genomic DNA was genotyped for polymorphic variations, and allele frequencies were tested for the Hardy–Weinberg disequilibrium in 240 ethnic Kashmiri cases with high myopia with a spherical equivalent of >−6 diopters (D) and compared with emmetropic controls with spherical equivalent within −0.5D in one or both eyes represented by a sample size of 228. In this study, we found a novel sequence variation G26A (GAT to AAT) in 5′ half of TGIF1 gene (p. aspartic acid >asparagine) at a frequency of 62% (148/240, P ≤ 0.0001). Variation appears to associate with high myopia significantly (P ≤ 0.001) as it happens to be present only in high myopia affected individuals. Further, it shows statistical significance for its association with gender and the degree of myopia (P ≤ 0.05). In addition, in silico predictions show that variation likely has an impact on the structure and functional properties of the protein. The assessment of the I-TASSER protein structure showed higher energy for a wild-type protein (−5820.186 kJ/mol) as compared to mutant protein (−6595.593 kJ/mol).

Genomic Changes in Pediatric Renal Transplant Patients Detected by aCGH

Introduction Acute and chronic allograft rejection are major problems in kidney transplantation. Identifying differences among individuals at the genomic level might help us to understand the rationale of tissue and organ rejection. The aim of this study is to identify the copy losses and gains in the genomes of patients experienced rejection in acute and chronic terms. Materials and Methods This study was designed as a retrospective single center study. A total of 24 pediatric renal transplant patients (F/M:10/14) were enrolled in the study. Patients were divided into 3 groups which are 8 kidney transplantation patients without rejection, 8 patients with acute rejection and 8 patients with chronic rejection. Agilent SurePrint G3 Human CGH 60K arrays were used to identify genome wide copy number variations. Results Mean transplant age of the non-rejection group, acute rejection, and chronic rejections patients were 15.8±4.2, 13.2±2.7, 16.4±3.8 years respectively. Average rejection time for acute and chronic rejection patients was 16.9±9.7 and 26.4±6.7 months, respectively. Results of the aCGH analysis showed that copy number losses were detected on chromosomes 1q42.2-q42.3, 2q13, 4q31.1, 7q11.23, 11q13.2, 14q11.2, 20q13.32, and copy number gains were detected on chromosomes 1p36.13, 1p32.3, 2p24.1, 2p21, 3q23, 5p13.2, 11q13.2, 12q24.21, 13q12.12, 16p11.2, 18p11.31, 19q13.43, 20p13, 20q11.21, 21q22.12, 21q22.2. Copy number variations were detected in patients with acute and chronic kidney rejection group but not in the non-rejection group. Discussion The management of acute and chronic allograft transplantation rejection is one of the major concerns during the follow up of transplantation patients. Nevertheless standardized protocols and well tuned immunosuppressant therapies are used in transplant patients; interindividual differences can cause different responses to drugs. In this study, we identified several genomic loci that show differences in terms of copy number state among patient groups. 18p11.31 is one of the loci identified in this study. TGIF1 gene within this region was reported to be over-expressed previously in kidney transplantation patients who experienced chronic rejection, which supports our finding that overexpression could be due to gain detected. Conclusion In this study, we identified copy number differences among kidney transplantation patients which might be important for the short and long term graft survival. Each region and genes within these regions could be individual possible biomarker to predict graft health.

TGIF1 splicing variant 8 is overexpressed in oral squamous cell carcinoma and is related to pathologic and clinical behavior

Possible differences in splicing variants of TGIF1 in oral squamous cell carcinoma (OSCC) have not yet been reported. This study analyzed the expression levels of different splicing variants of the TGIF1 gene in OSCC compared with nontumoral epithelium (NT) and the relationship with clinical-pathologic features of tumors. Forty-eight frozen samples of OSCC and 17 of NT were analyzed using quantitative reverse transcription polymerase chain reaction. TGIF1v2 and v8 are overexpressed in OSCC, whereas TGIF1v5 is underexpressed when compared with NT. Low TGIF1v8 expression was correlated with lower cellular differentiation, positive blood vascular invasion, advanced pathologic stage, and positive vascular lymphatic invasion of OSCC. TGIF1v8 is also related to overall survival over time, with lower values associated with an increased risk of cancer-related death. These data suggest that alternative splicing of TGIF1 is deregulated in OSCC, with overexpression of some splicing variants, especially TGIF1v8, which is associated with advanced stages of OSCC.

Could a mutation in the TGIF-1 gene result in phenotypical expressions like pachygyria, intracerebral calcification, and neonatal epilepsy?

Mutations of the TGIF-1 gene in humans may be seen in connection with various complex malformation syndromes. Phenotypical expression may include microcephaly, hypotelorism, a single large incisor, clefts of lip and palate, and structural abnormalities of the brain (holoprosencephaly, corpus callosum malformation). Carriers of the mutation without physical signs have been described.

Pituitary Stalk Interruption Syndrome and Isolated Pituitary Hypoplasia May Be Caused by Mutations in Holoprosencephaly-Related Genes

Holoprosencephaly (HPE) is a developmental defect characterized by wide phenotypic variability, ranging from minor midline malformations (eg, single central incisor) to severe deformities. In 10-15% of HPE patients, mutations in specific genes have been identified (eg, SHH, TGIF, SIX3). Pituitary stalk interruption syndrome (PSIS) constitutes a distinct abnormality of unknown pathogenesis, whereas isolated pituitary hypoplasia (IPH) has been linked to various developmental genes. Three of our patients with PSIS had a single central incisor, a malformation encountered in some HPE cases. Based on this observation, we initiated a search for mutations in HPE-associated genes in 30 patients with PSIS or IPH. The entire coding region of the TGIF, SHH, and SIX3 genes was sequenced in patients with combined pituitary hormone deficiency associated with either PSIS or IPH and in healthy controls. Two novel mutations in the HPE-related genes were detected (ie, c.799 C>T, p.Q267X in the TGIF gene, and c.1279G>A, p.G427R in the SHH gene) in 2 of our patients. The overall incidence of HPE-related gene mutations in our nonsyndromic and nonchromosomal patients was 6.6%. No molecular defect in the SIX3 gene was detected in our cohort. The data suggest that HPE-related gene mutations are implicated in the etiology of isolated pituitary defects (PSIS or IPH). Alternatively, PSIS or IPH may constitute mild forms of an expanded HPE spectrum.

Loss of Tgif Function Causes Holoprosencephaly by Disrupting the Shh Signaling Pathway

Holoprosencephaly (HPE) is a severe human genetic disease affecting craniofacial development, with an incidence of up to 1/250 human conceptions and 1.3 per 10,000 live births. Mutations in the Sonic Hedgehog (SHH) gene result in HPE in humans and mice, and the Shh pathway is targeted by other mutations that cause HPE. However, at least 12 loci are associated with HPE in humans, suggesting that defects in other pathways contribute to this disease. Although the TGIF1 (TG-interacting factor) gene maps to the HPE4 locus, and heterozygous loss of function TGIF1 mutations are associated with HPE, mouse models have not yet explained how loss of Tgif1 causes HPE. Using a conditional Tgif1 allele, we show that mouse embryos lacking both Tgif1 and the related Tgif2 have HPE-like phenotypes reminiscent of Shh null embryos. Eye and nasal field separation is defective, and forebrain patterning is disrupted in embryos lacking both Tgifs. Early anterior patterning is relatively normal, but expression of Shh is reduced in the forebrain, and Gli3 expression is up-regulated throughout the neural tube. Gli3 acts primarily as an antagonist of Shh function, and the introduction of a heterozygous Gli3 mutation into embryos lacking both Tgif genes partially rescues Shh signaling, nasal field separation, and HPE. Tgif1 and Tgif2 are transcriptional repressors that limit Transforming Growth Factor β/Nodal signaling, and we show that reducing Nodal signaling in embryos lacking both Tgifs reduces the severity of HPE and partially restores the output of Shh signaling. Together, these results support a model in which Tgif function limits Nodal signaling to maintain the appropriate output of the Shh pathway in the forebrain. These data show for the first time that Tgif1 mutation in mouse contributes to HPE pathogenesis and provide evidence that this is due to disruption of the Shh pathway.

New Syndrome of Congenital Circumferential Skin Folds Associated with Multiple Congenital Anomalies

Congenital circumferential skin folds can be found in individuals with no additional defects, as well as in patients with multiple congenital anomalies and developmental abnormalities. Current data point to etiological heterogeneity of syndromic cases. We describe a 7-month-old girl with a novel combination of symmetrical congenital circumferential skin folds, dysmorphic features, and multiple congenital abnormalities. Examination of the patient revealed symmetrical congenital circumferential skin folds and dysmorphic features, as well as multiple congenital anomalies including nasal pyriform aperture stenosis, ventricular septal defect, absent spleen, camptodactyly, and severe psychomotor retardation. Skin biopsy demonstrated subcutaneous fat extending into the superficial and deep reticular dermis. Sequencing of the CDON, SHH, ZIC2, SIX3, and TGIF genes (associated with holoprosencephaly) did not disclose pathogenic alterations. Extensive review of previously described cases of syndromic congenital circumferential skin folds did not reveal a similar combination of clinical and histopathological findings.

Fetal RHD genotype detection from circulating cell‐free fetal DNA in maternal plasma in non‐sensitized RhD negative women

To examine the performance of the SensiGene Fetal RHD Genotyping Laboratory Developed Test (RHD Genotyping LDT) using circulating cell-free fetal DNA (ccff DNA) extracted from maternal plasma. ccff DNA was extracted from maternal blood from non-sensitized women with singleton pregnancies in two cohorts, one with a serotype reference (11-13 weeks' gestation) and one with the reference source (6-30 weeks' gestation). The presence of three RHD exon sequences (exons 4, 5, 7), the psi-pseudogene, three Y-chromosome sequences (SRY, DBY and TTTY2), and the X/Y-chromosome TGIF gene control were determined using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry-the RHD Genotyping LDT. The cohort with a serotype RhD reference showed correct classification in 201 of 207 patients, a test accuracy of 97.1%, with a sensitivity and specificity for prediction of RhD serotype of 97.2 and 96.8%, respectively. The cohort with a genotype RHD reference showed correct classification in 198 of 199 patients, indicating a test accuracy of 99.5% with a sensitivity and specificity for prediction of RHD genotype of 100.0 and 98.3%, respectively. Fetal RHD genotyping can accurately be determined using ccff DNA in the first and second trimesters of pregnancy.

The unfolding clinical spectrum of holoprosencephaly due to mutations in SHH, ZIC2, SIX3 and TGIF genes.

Holoprosencephaly is a severe malformation of the brain characterized by abnormal formation and separation of the developing central nervous system. The prevalence is 1:250 during early embryogenesis, the live-born prevalence is 1:16 000. The etiology of HPE is extremely heterogeneous and can be teratogenic or genetic. We screened four known HPE genes in a Dutch cohort of 86 non-syndromic HPE index cases, including 53 family members. We detected 21 mutations (24.4%), 3 in SHH, 9 in ZIC2 and 9 in SIX3. Eight mutations involved amino-acid substitutions, 7 ins/del mutations, 1 frame-shift, 3 identical poly-alanine tract expansions and 2 gene deletions. Pathogenicity of mutations was presumed based on de novo character, predicted non-functionality of mutated proteins, segregation of mutations with affected family-members or combinations of these features. Two mutations were reported previously. SNP array confirmed detected deletions; one spanning the ZIC2/ZIC5 genes (approx. 100 kb) the other a 1.45 Mb deletion including SIX2/SIX3 genes. The mutation percentage (24%) is comparable with previous reports, but we detected significantly less mutations in SHH: 3.5 vs 10.7% (P=0.043) and significantly more in SIX3: 10.5 vs 4.3% (P=0.018). For TGIF1 and ZIC2 mutation the rate was in conformity with earlier reports. About half of the mutations were de novo, one was a germ line mosaic. The familial mutations displayed extensive heterogeneity in clinical manifestation. Of seven familial index patients only two parental carriers showed minor HPE signs, five were completely asymptomatic. Therefore, each novel mutation should be considered as a risk factor for clinically manifest HPE, with the caveat of reduced clinical penetrance.

A conserved gene regulatory network subcircuit drives different developmental fates in the vegetal pole of highly divergent echinoderm embryos

Comparisons of orthologous developmental gene regulatory networks (GRNs) from different organisms explain how transcriptional regulation can, or cannot, change over time to cause morphological evolution and stasis. Here, we examine a subset of the GRN connections in the central vegetal pole mesoderm of the late sea star blastula and compare them to the GRN for the same embryonic territory of sea urchins. In modern sea urchins, this territory gives rise to skeletogenic mesoderm; in sea stars, it develops into other mesodermal derivatives. Orthologs of many transcription factors that function in the sea urchin skeletogenic mesoderm are co-expressed in the sea star vegetal pole, although this territory does not form a larval skeleton. Systematic perturbation of erg, hex, tbr, and tgif gene function was used to construct a snapshot of the sea star mesoderm GRN. A comparison of this network to the sea urchin skeletogenic mesoderm GRN revealed a conserved, recursively wired subcircuit operating in both organisms. We propose that, while these territories have evolved different functions in sea urchins and sea stars, this subcircuit is part of an ancestral GRN governing echinoderm vegetal pole mesoderm development. The positive regulatory feedback between these transcription factors may explain the conservation of this subcircuit.

Transforming Growth Factors β Coordinate Cartilage and Tendon Differentiation in the Developing Limb Mesenchyme

Transforming growth factor beta (TGFbeta) signaling has an increasing interest in regenerative medicine as a potential tool to repair cartilages, however the chondrogenic effect of this pathway in developing systems is controversial. Here we have analyzed the function of TGFbeta signaling in the differentiation of the developing limb mesoderm in vivo and in high density micromass cultures. In these systems highest signaling activity corresponded with cells at stages preceding overt chondrocyte differentiation. Interestingly treatments with TGFbetas shifted the differentiation outcome of the cultures from chondrogenesis to fibrogenesis. This phenotypic reprogramming involved down-regulation of Sox9 and Aggrecan and up-regulation of Scleraxis, and Tenomodulin through the Smad pathway. We further show that TGFbeta signaling up-regulates Sox9 in the in vivo experimental model system in which TGFbeta treatments induce ectopic chondrogenesis. Looking for clues explaining the dual role of TGFbeta signaling, we found that TGFbetas appear to be direct inducers of the chondrogenic gene Sox9, but the existence of transcriptional repressors of TGFbeta signaling modulates this role. We identified TGF-interacting factor Tgif1 and SKI-like oncogene SnoN as potential candidates for this inhibitory function. Tgif1 gene regulation by TGFbeta signaling correlated with the differential chondrogenic and fibrogenic effects of this pathway, and its expression pattern in the limb marks the developing tendons. In functional experiments we found that Tgif1 reproduces the profibrogenic effect of TGFbeta treatments.

Array-CGH analysis indicates a high prevalence of genomic rearrangements in holoprosencephaly: An updated map of candidate loci

Holoprosencephaly (HPE) is the most frequent malformation of the brain. To date, 12 different HPE loci and 8 HPE genes have been identified from recurrent chromosomal rearrangements or from the sequencing of genes from Nodal and SHH pathways. Our cohort of HPE patients presents a high genetic heterogeneity. Point mutations were found in SHH, ZIC2, SIX3, and TGIF genes in about 20% of cases (with 10% in SHH). Deletions in these same genes were found in 7.5% of the patients and 4.4% presented with other subtelomeric gain or losses. Consequently, the molecular basis of HPE remains unknown in 70% of our cohorts. To detect new HPE candidate genes, we used array-CGH to refine the previous karyotype based HPE loci map. We analyzed 111 HPE patients with high-performance Agilent oligonucleotidic arrays and found that 28 presented anomalies involving known or new potential HPE loci located on different chromosomes but with poor redundancy. This study showed an impressive rate of 19 patients among 111 with de novo chromosomal anomalies giving evidence that microrearrangements could be a major molecular mechanism in HPE. Additionally, this study opens new insights on HPE candidate genes identification giving an updated HPE candidate loci map.

High Myopia Is Not Associated with the SNPs in theTGIF, Lumican,TGFB1, andHGFGenes

Four single-nucleotide polymorphisms (SNPs) in the TGIF, lumican, TGFB1, and HGF genes have been declared to be associated with high myopia in Chinese living in southeast China, but none of them has been confirmed by additional studies. This study was conducted to verify the reported positive association results by analysis of subjects from the same region. DNA was prepared from venous leukocytes of 288 patients with high myopia and 208 control subjects. The four SNPs (rs2229336, rs3759223, rs1982073, and rs3735520) in the four genes were genotyped by restriction fragment length polymorphism (RFLP) analysis. The allele and genotype frequencies of these SNPs from patients and control subjects were compared by chi(2) test. Polymorphism at rs2229336 was not detected in all 496 subjects. There were no statistically significant differences between patients and control subjects for the other three SNPs: rs3759223, rs1982073, and rs3735520. The study does not support the association of high myopia with alleles of rs2229336 in TGIF, rs3759223 in lumican, rs1982073 in TGFB1, and rs3735520 in HGF. These results provide a view contrary to those in previous reports. Reasonable criteria as well as replication should be the first priority for genetic association studies to avoid excessive expansion of false-positive results, especially for high myopia.

Variable phenotypic manifestations of a K44N mutation in the TGIF gene

The etiologies and clinical spectra of HPE are extremely heterogeneous. Here, we report a Brazilian boy with lobar holoprosencephaly who was ascertained in a sample of 60 patients with HPE and HPE-like phenotypes and screened for molecular analysis of the major HPE causative genes: SHH, PTCH, SIX3, GLI2, and TGIF. This boy presented a p.K44N (c.132G > T) mutation in exon 2 of the TGIF gene which was inherited from his phenotypically normal mother. This mutation leads to lysine to arginine amino acid change and is predicted to be a damaging mutation. Clinical aspects involving variable phenotypical manifestations in different mutations of TGIF are discussed.

Linkage Mapping of Ovine Microphthalmia to Chromosome 23, the Sheep Orthologue of Human Chromosome 18

To characterize the phenotype and map the locus responsible for autosomal recessive inherited ovine microphthalmia (OMO) in sheep. Microphthalmia-affected lambs and their available relatives were collected in a field, and experimental matings were performed to obtain affected and normal lambs for detailed necropsy and histologic examinations. The matings resulted in 18 sheep families with 48 cases of microphthalmia. A comparative candidate gene approach was used to map the disease locus within the sheep genome. Initially, 27 loci responsible for the microphthalmia-anophthalmia phenotypes in humans or mice were selected to test for comparative linkage. Fifty flanking markers that were predicted from comparative genomic analysis to be closely linked to these genes were tested for linkage to the disease locus. After observation of statistical evidence for linkage, a confirmatory fine mapping strategy was applied by further genotyping of 43 microsatellites. The clinical and pathologic examinations showed slightly variable expressivity of isolated bilateral microphthalmia. The anterior eye chamber was small or absent, and a white mass admixed with cystic spaces extended from the papilla to the anterior eye chamber, while no recognizable vitreous body or lens was found within the affected eyes. Significant linkage to a single candidate region was identified at sheep chromosome 23. Fine mapping and haplotype analysis assigned the candidate region to a critical interval of 12.4 cM. This ovine chromosome segment encompasses an ancestral chromosomal breakpoint corresponding to two orthologue segments of human chromosomes 18, short and long arms. For the examined animals, we excluded the complete coding region and adjacent intronic regions of ovine TGIF1 to harbor disease-causing mutations. This is the first genetic localization for hereditary ovine isolated microphthalmia. It seems unlikely that a mutation in the TGIF1 gene is responsible for this disorder. The studied sheep represent a valuable large animal model for similar human ocular phenotypes.

Intragenic deletion of Tgif causes defectsin brain development

TG-interacting factor (TGIF) is a homeodomain-containing protein and functions as a transcriptional repressor within the TGF-beta and retinoic acid signaling pathways. Heterozygous mutations of TGIF have been found in patients with holoprosencephaly (HPE), which is the most common congenital brain malformation in humans. However, targeted null deletions of the entire Tgif gene in mice surprisingly revealed no apparent brain defects. We report here that deletion of the third exon of Tgif gene resulted in a defined spectrum of brain developmental defects including exencephaly, microcephaly, HPE, and abnormalities in embryonic brain ventricle formation and cleavage. These defects could be detected in mice both heterozygous and homozygous for the targeted Tgif deletion. Moreover, expression of dorsal-ventral patterning genes including Shh, Pax6 and Nkx2.2 was altered. The ventricular neuroepithelium exhibited focalized increase of cell proliferation rate and resultant tissue expansion. The incidence of brain abnormalities within the mutant mice was dependent on its genetic background, suggesting that additional genetic modifiers functionally interact with Tgif during embryonic brain development. The intragenic Tgif deletion mouse, therefore, would serve as a useful model that can be used to unravel the genetic complexity implicated in the pathogenesis of HPE.

Functional analysis of mutations in TGIF associated with holoprosencephaly

Holoprosencephaly (HPE) is the most common structural malformation of the forebrain and face in humans. Our current understanding of the pathogenesis of HPE attempts to integrate genetic susceptibility, evidenced by mutations in the known HPE genes, with the epigenetic influence of environmental factors. Mutations or deletions of the human TGIF gene have been associated with HPE in multiple population cohorts. Here we examine the functional effects of all previously reported mutations, and describe four additional variants. Of the eleven sequence variations in TGIF, all but four can be demonstrated to be functionally abnormal. In contrast, no potentially pathogenic sequence alterations were detected in the related gene TGIF2. These results provide further evidence of a role for TGIF in HPE and demonstrate the importance of functional analysis of putative disease-associated alleles.

A novel heterozygous missense mutation 377T > C (V126A) of TGIF gene in a family segregated with holoprosencephaly and moyamoya disease

To identify whether any mutations of candidate genes including SHH, ZIC2, SIX3, and TGIF exist in a Taiwanese family segregated with holoprosencephaly (HPE) and moyamoya disease. Genotypes of the candidate genes SHH, ZIC2, SIX3, and TGIF were determined in the family members who were available for analysis by sequencing. In addition, genomic regions of another 50 unrelated Taiwanese (100 chromosomes) were studied to verify whether the nucleotide changes we found were mutations or polymorphisms. A novel missense mutation 377T > C and two polymorphisms (420A > G and 487C > T) in the TGIF gene were identified. No mutations in SHH, ZIC2 and SIX3 were found. The mother of the three HPE fetuses was found to be afflicted with moyamoya disease. A brief review of the mutations as well as polymorphisms reported in the TGIF gene up to 2005 is given. Molecular diagnosis can help genetic counseling in HPE, which is a heterogeneous disorder with its phenotypic and genotypic spectrum highly widened and variable. The possible association between TGIF mutation and moyamoya disease noted in our study also appeared to be novel.