Novel c.300_301delinsT mutation in PITX2 in a Korean family with Axenfeld-Rieger syndrome.
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ABSTRACT:
SUBMITTER: Yun JW
PROVIDER: S-EPMC3756242 | biostudies-literature | 2013 Sep
REPOSITORIES: biostudies-literature
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Novel c.300_301delinsT mutation in PITX2 in a Korean family with Axenfeld-Rieger syndrome.
Yun Jae Won JW Cho Hyun-Kyung HK Oh Soo-Young SY Ki Chang-Seok CS Kee Changwon C
Annals of laboratory medicine 20130808 5
Axenfeld-Rieger syndrome (ARS) is characterized by anomalies of the anterior segment of the eye and systemic abnormalities. Mutations in the FOXC1 and PITX2 genes are underlying causes of ARS, but there has been few reports on genetically confirmed ARS in Korea. We identified a novel PITX2 mutation (c.300_301delinsT) in 2 Korean patients from a family with ARS. We expand the spectrum of PITX2 mutations and, to the best of our knowledge, this is the first confirmed family of PITX2-related ARS in ...[more]
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Project description:PurposeAxenfeld-Rieger syndrome (ARS) is an autosomal dominant disorder characterized by extraocular anomalies and developmental defects of the anterior segment. PITX2 (paired-like homeodomain transcription factor 2) is considered the major causative gene. In this study, we characterized the molecular defect in PITX2 in a Chinese family with ARS.MethodsTwo generations of the family with ARS were enrolled in the present study. In addition to ophthalmologic examinations, polymerase chain reaction (PCR) amplification and nucleotide sequencing of all coding exons of PITX2 were performed. Exon 5 (region 1) was also sequenced in 100 healthy controls unrelated to the family for comparison.ResultsA novel PITX2 mutation, c.840G>T, was identified in all affected members of the family with ARS that causes an amino acid substitution from tryptophan to cysteine at codon 86.ConclusionsWe found a novel p.W86C mutation in PITX2 in a Chinese family with ARS. The tryptophan residue at position 86 is strictly conserved in PITX2a proteins from several species and in homeodomain proteins. We suggest that this mutation in PITX2 is the cause of typical ARS in patients. Our results may be useful for better understanding of the spectrum of PITX2 mutations and the role of PITX2 in the development and progression of ARS.
| S-EPMC2592999 | biostudies-literature
Project description:OBJECTIVE: Axenfeld-Rieger syndrome (ARS) is phenotypically and genetically heterogeneous. In this study, we identified the underlying genetic defect in a Chinese family with ARS. METHODS: A detailed family history and clinical data were recorded. The ocular phenotype was documented using slit-lamp photography and systemic anomalies were also documented where available. The genomic DNA was extracted from peripheral blood leukocytes. All coding exons and intron-exon junctions of paired-like homeodomain transcription factor 2 (PITX2) gene and the forkhead box C1 (FOXC1) gene were amplified by polymerase chain reaction (PCR) and screened for mutation by direct DNA sequencing. Variations detected in exon 5 of PITX2 were further evaluated with cloning sequencing. The exon 5 of PITX2 was also sequenced in 100 healthy controls, unrelated to the family, for comparison. Structural models of the wild type and mutant homeodomain of PITX2 were investigated by SWISS-MODEL. RESULTS: Affected individuals exhibited variable ocular phenotypes, whereas the systemic anomalies were similar. After direct sequencing and cloning sequencing, a heterozygous deletion/insertion mutation c.198_201delinsTTTCT (p.M66Ifs*133) was revealed in exon 5 of PITX2. This mutation co-segregated with all affected individuals in the family and was not found either in unaffected family members or in 100 unrelated controls. CONCLUSIONS: We detected a novel frameshift mutation p.M66Ifs*133 in PITX2 in a Chinese family with ARS. Although PITX2 mutations and polymorphisms have been reported from various ethnic groups, we report for the first time the identification of a novel deletion/insertion mutation that causes frameshift mutation in the homeodomain of PITX2 protein.
| S-EPMC3891117 | biostudies-literature
Project description:Axenfeld-Rieger syndrome is a rare autosomal dominant condition. Anomalies include anterior segment dysgenesis of the eye, dental anomalies, maxillary hypoplasia, periumbilical anomalies, and congenital heart defects. We report a patient with Peters anomaly, dysmorphic features, congenital heart defect, umbilical hernia, short stature, and developmental delay. Diagnostic sequencing of 23 genes known to be causally related to the condition was performed on the patient, parents, and maternal grandparents. A variant of uncertain significance in PITX2 was identified. The mother had the same mutation and the father did not. The mother had decreased vision, congenitally missing teeth, and required jaw surgery as a child. Her asymptomatic parents elected to be tested and were negative for the mutation. The mutation, NM_153427.2:c.272G>A (p.Arg91Gln), is predicted to be damaging by PolyPhen-2 (score of 0.997), identified as a missense mutation with an allele frequency of 1.648e-05 by the Exome Aggregation Consortium, and has been reported in ClinVar once, by the laboratory that analyzed our patient's sample. Due to the in silico predictions and the results of family studies, it is suggested that this variant can be classified as pathogenic according to the American College of Medical Genetics and Genomics 2015 rule Pathogenic(iii)(b), specifically rules PS2, PM2, PM5, PP1, and PP3.
| S-EPMC5465683 | biostudies-literature
Project description:PURPOSE: To report a case series of patients with novel forkhead box CI (FOXC1) mutations in a Korean family with Axenfeld-Rieger syndrome (ARS). METHODS: Four members of the same family underwent complete ophthalmologic and systemic examinations and genetic analysis. Genomic DNA was isolated from peripheral blood leukocytes, and all coding exons with flanking intronic regions of the FOXC1 and pituitary homeobox 2 genes were amplified using PCR, and sequenced. RESULTS: The patients were 40, 12, 11, and 10 years old (father, son, and two sisters, respectively). All four had uncontrolled intraocular pressure, glaucomatous visual field defect, retinal nerve fiber layer defect, iridocorneal adhesion on gonioscopy, hypoplasia and marked atrophy of the iris, flattening of the midface, and broad flat noses. A diagnosis of ARS was made based on characteristic ocular and systemic traits. A novel FOXC mutation, c.317delA, was identified in all affected members of the family with ARS. CONCLUSIONS: We found a novel c.317delA mutation in FOXC1 in a Korean family with ARS. We suggest that this FOXC1 mutation causes typical ARS, and that our results may be useful for better understanding of the spectrum of FOXC1 mutations and the role of FOXC1 in the development and progression of ARS.
| S-EPMC3654851 | biostudies-other
Project description:Axenfeld-Rieger syndrome (ARS) (OMIM Nr.: 180500) is a rare autosomal dominant disorder (1 : 200000) with genetic and morphologic variability. Glaucoma is associated in 50% of the patients. Craniofacial and dental anomalies are frequently reported with ARS. The present study was designed as a multidisciplinary analysis of orthodontic, ophthalmologic, and genotypical features. A three-generation pedigree was ascertained through a family with ARS. Clinically, radiographic and genetic analyses were performed. Despite an identical genotype in all patients, the phenotype varies in expressivity of craniofacial and dental morphology. Screening for PITX2 and FOXC1 mutations by direct DNA-sequencing revealed a P64L missense mutation in PITX2 in all family members, supporting earlier reports that PITX2 is an essential factor in morphogenesis of teeth and craniofacial skeleton. Despite the fact that the family members had identical mutations, morphologic differences were evident. The concomitant occurrence of rare dental and craniofacial anomalies may be early diagnostic indications of ARS. Early detection of ARS and elevated intraocular pressure (IOP) helps to prevent visual field loss.
| S-EPMC2842968 | biostudies-literature
Project description:PurposeThe aims of this study were to examine novel mutations in PITX2 and FOXC1 in Chinese patients with anterior segment dysgenesis (ASD) and to compare the clinical presentations of these mutations with previously reported associated phenotypes.MethodsTwenty-six unrelated patients with different forms of ASD were enrolled from our paediatric and genetic eye clinic. The ocular manifestations of both eyes of each patient were recorded. Genomic DNA was prepared from venous leukocytes. All coding exons of PITX2 and FOXC1 were amplified by polymerase chain reaction (PCR) from genomic DNA and subjected to direct DNA sequencing. Analysis of mutations in control subjects was performed by heteroduplex single-strand conformation polymorphism (SSCP) analysis.ResultsSequence analysis of the PITX2 gene revealed four mutations, including c.475_476delCT (P.L159VfsX39), c.64C > T (P.Q22X), c.296delG (P.R99PfsX56), and c.206G > A (P.R69H). The first three mutations were found to be novel. The c.475_476delCT (P.L159VfsX39) mutation, located at the 3' end of the PITX2-coding region, was identified in a Chinese Axenfeld-Rieger syndrome (ARS) patient who presented with an unusual severe phenotype of bilateral aniridia. The clinical characteristics, including the severity and manifestations of the patient's phenotype, were compared with reported PITX2-associated aniridia phenotypes of ARS in the literature.ConclusionsThese results expand the mutation spectrum of the PITX2 gene in patients with ARS. The PITX2 gene may be responsible for a significant portion of ARS with additional systemic defects in the Chinese population. This is the first reported case of a mutation at the 3' end of the PITX2-coding region extending the phenotypic consequences to bilateral aniridia. The traits of ARS could display tremendous variability in severity and manifestations due to the dominant-negative effect of PITX2. Our results further emphasize the importance of careful clinical and genetic analysis in determining mutation-disease associations and may lead to a better understanding of the role of PITX2 in ocular development.
| S-EPMC6636469 | biostudies-literature
Project description:PurposeAxenfeld-Rieger syndrome (ARS) is an autosomal dominant disorder characterized by ocular anterior segment abnormalities. In the current study, we describe clinical and genetic findings in a Chinese ARS pedigree.MethodsAn ARS pedigree was recruited and patients were given comprehensive ophthalmic examinations and general physical examinations. DNA from the proband II:2 was used for exome sequencing. Sanger sequencing was utilized to identify and validate PITX2 variations. qPCR and western blotting were performed to detect PITX2 expression in immortalized peripheral blood lymphocytes.ResultsAll affected family members showed typical ocular abnormalities, including iris atrophy, corectopia, shallow anterior chamber, complete or partial angle closure, and advanced glaucoma. They also exhibited systemic anomalies, such as microdontia, hypodontia, and redundant periumbilical skin. A heterozygous splice-site variation c.390 + 1G > A in PITX2, which might lead to a truncated PITX2 protein (p.Val131IlefsX127), was found in the proband. Sanger sequencing validated that the variation completely co-segregated with the ARS phenotype within this family and was absent in 100 unrelated controls. Western blotting revealed that the nuclear PITX2 protein was significantly decreased in patients compared with controls. Nonetheless, there was no significant difference in the total PITX2 protein level, consistent with qPCR results showing no alteration in PITX2 mRNA levels in the patient group.ConclusionsPITX2 c.390 + 1G > A (p.Val131IlefsX127) was a novel genetic etiology of the ARS pedigree. The mutation leads to decreased nuclear PITX2, indicating lower transcriptional activity.
| S-EPMC8035109 | biostudies-literature
Project description:Axenfeld-Rieger syndrome (ARS) is a rare autosomal dominant disorder, which encompasses a range of congential malformations affecting the anterior segment of the eye. ARS shows genetic heterogeneity and mutations of the two genes, PITX2 and FOXC1, are known to be associated with the pathogenesis. There are several excellent reviews dealing with the complexity of the phenotype and genotype of ARS. In this study, we will attempt to give a brief review of the clinical features and the relevant diagnostic approaches, together with a detailed review of published PITX2 and FOXC1 mutations.
| S-EPMC2987033 | biostudies-literature
Project description:Purpose:To identify the genetic cause in a four-generation Chinese family with Axenfeld-Rieger syndrome (ARS). Methods:The family members received clinical examinations of the eye, tooth, periumbilical skin, and heart. Sanger sequencing and whole-exome sequencing (WES) were performed to screen potential mutations. The genomic deletion region around the PITX2 gene was estimated from single nucleotide polymorphism (SNP) data from WES and then confirmed with "quantitative PCR (qPCR) using a set of primers. The DNA breakpoint was further identified with long-range PCR and Sanger sequencing. Results:Symptoms including anterior segment dysplasia of the eye (iris dysplasia, multiple pupils, and posterior embryotoxon), dental dysplasia, and periumbilical skin redundancy were present in all of the affected individuals. Three of them had glaucoma. Corneal abnormalities (inferior sclerocornea, corneal endothelial dystrophy, and central corneal scar) were seen in most of the affected individuals. Cataract, limited eye movement, electrocardiographic abnormalities, intellectual disability, and recurrent miscarriages were observed in some of the affected individuals. No mutations in the coding and exon-intron adjacent regions of the PITX2 and FOXC1 genes were identified with Sanger sequencing. According to the SNP data from WES, we suspected that there might be a deletion region (at most 1.6 Mb) around the PITX2 gene. With the use of qPCR and long-range PCR, we identified a 53,840 bp deletion (chr4: 111,535,454-111,588,933) spanning PITX2 and PANCR. The genomic deletion cosegregated with the major ARS symptoms observed in the family members. Conclusions:With the help of WES, qPCR, and long-range PCR, we identified a genomic deletion encompassing PITX2 and the adjacent noncoding gene PANCR in a Chinese family with ARS. The clinical features of the affected individuals are reported. This work may broaden understanding of the phenotypic and mutational spectrums related to ARS.
| S-EPMC7553719 | biostudies-literature
Project description:PurposeAxenfeld-Rieger syndrome (ARS) is a rare autosomal dominant disorder that affects the anterior segment of the eye. The aim of this study was to examine the PITX2 gene to identify possible novel mutations in Pakistani and Mexican families affected by the ARS phenotype.MethodsThree unrelated probands with a diagnosis of ARS were recruited for this study. Genomic DNA was isolated from the peripheral blood of the probands and their family members. Polymerase chain reaction and Sanger sequencing were used for the analysis of coding exons and the flanking intronic regions of the PITX2 gene. Bioinformatics tools and database (VarSome, Provean, and MutationTaster, SIFT, PolyPhen-2, and HOPE) were evaluated to explore missense variants.ResultsWe identified novel heterozygous variations in the PITX2 gene that segregated with the ARS phenotype within the families. The variant NM_153426.2(PITX2):c.226G > T or p.(Ala76Ser) and the mutation NM_153426.2(PITX2):c.455G > A or p.(Cys152Tyr) were identified in two Pakistani pedigrees, and the mutation NM_153426.2(PITX2):c.242_265del or p.(Lys81_Gln88del), segregated in a Mexican family.ConclusionOur study extends the spectrum of PITX2 mutations in individuals with ARS, enabling an improved diagnosis of this rare but serious syndrome.
| S-EPMC7336731 | biostudies-literature