Screening of pathogenic mutation in a family with Axenfeld-Rieger syndrome by whole exome sequencing / 中华实验眼科杂志

Objective:To identify disease-causing variation in a Chinese family with Axenfeld-Rieger syndrome (ARS) through the analysis of clinical symptoms and hereditary information.Methods:The method of pedigree investigation was adopted.A Chinese ARS family including 15 family members of 3 generations was recruited in the Second Affiliated Hospital of Harbin Medical University in 2018.There were 3 patients in the family.The family history and clinical data were collected.Ophthalmic and general examinations were carried out in all the members included.DNA and RNA were extracted from collected peripheral venous blood samples of 2-5 ml from each member.Whole exome sequencing was used to screen the variations in the proband.Suspected variations screened through searching population databases and bioinformatics analysis were verified by Sanger sequencing and real-time quantitative PCR.Conservation analysis and deleteriousness prediction of suspected variations were conducted.The pathogenecity of candidate rare variations were evaluated according to the American College of Medical Genetics and Genomics (ACMG) standards and guidelines.This study followed the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of the Second Affiliated Hospital of Harbin Medical University (No.KY2019-231).Written informed consent was obtained from each subject or custodian prior to entering the study cohort.Results:The 3 patients all had typical ARS clinical features in eyes, teeth and umbilicus, and carried the same heterozygous variant, c.525delC (p.Asp175Glufs *) in the PITX2 gene, which were not found in other members, indicating co-segregation.The relative expression of PITX2 mRNA was 0.672±0.063 in the patients, which was significantly lower than 1.015±0.179 in the healthy controls ( t=8.847, P<0.001).This variant was not recorded in dbSNP, 1000G, gnomeAD, ExAC, Korea1K and EVS databases, and it was labelled as deleterious by MutationTaster.The affected conservative amino acid sequences were found in 9 species.The variant was determined as pathogenic according to the ACMG standards and guidelines. Conclusions:The c.525delC (p.Asp175Glufs *) mutation of PITX2 gene is pathogenic in the pedigree.This is the first time that this mutation has been reported in Chinese family with ARS.

Relationship between the expression levels of PITX2 and KCNQ1 in left atrial appendage tissue and the clinical characteristics in atrial fibrillation patients after modified mini-maze procedure / 中国胸心血管外科临床杂志

@#Objective    To detect the expression of PITX2 and KCNQ1 in the left atrial appendage of patients with atrial fibrillation after modified mini-maze procedure, and to detect the clinical risk factors of different types of atrial fibrillation. Methods    We collected left atrial appendage tissue of 59 atrial fibrillation patients who received modified mini-maze procedure and left atrial appendectomy from February 2017 to August 2018. The expression levels of PITX2 and KCNQ1 of left atrial appendage tissue were quantitatively analyzed by western blotting assay between paroxysmal attial fibrillation and persistent atrial fibrillation groups. The correlation between protein expression and prognosis after surgery was also analyzed based on clinical data. Results    Binary-logistic regression analysis showed that KCNQ1 expression level was an independent risk factor for the progression from paroxysmal atrial fibrillation to persistent atrial fibrillation. Receiver operating characteristic (ROC) curve confirmed that KCNQ1 expression level (the ratio of KCNQ1 to actin in the analysis) was 0.60, which was the best cut-off point for the progression of paroxysmal atrial fibrillation to persistent atrial fibrillation. Conclusion    High expression of KCNQ1 in left atrial appendage is a risk factor for progression from paroxysmal atrial fibrillation to persistent atrial fibrillation.

Upregulation of PITX2 Promotes Letrozole Resistance Via Transcriptional Activation of IFITM1 Signaling in Breast Cancer Cells / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Although the interferon α (IFNα) signaling and the paired-like homeodomain transcription factor 2 (PITX2) have both been implicated in the progression of breast cancer (BCa), it remains obscure whether these two pathways act in a coordinated manner. We therefore aimed to elucidate the expression and function of PITX2 during the pathogenesis of endocrine resistance in BCa. MATERIALS AND METHODS: PITX2 expression was assessed in BCa tissues using quantitative reverse transcription polymerase chain reaction (RT-qPCR) and immunohistochemistry and in experimentally induced letrozole-resistant BCa cells using RT-qPCR and immunoblotting. Effects of PITX2 deregulation on BCa progression was determined by assessing MTT, apoptosis and xenograft model. Finally, using multiple assays, the transcriptional regulation of interferon-inducible transmembrane protein 1 (IFITM1) by PITX2 was studied at both molecular and functional levels. RESULTS: PITX2 expression was induced in letrozole-resistant BCa tissues and cells, and PITX2 induction by IFNα signaling powerfully protected BCa cells against letrozole insult and potentiated letrozole-resistance. Mechanistically, PITX2 enhanced IFNα-induced AKT activation by transactivating the transcription of IFITM1, thus rendering BCa cells unresponsive to letrozoleelicited cell death. Additionally, ablation of IFITM1 expression using siRNA substantially abolished IFNα-elicited AKT phosphorylation, even in the presence of PITX2 overexpression, thus sensitizing BCa cells to letrozole treatment. CONCLUSION: These results demonstrate that constitutive upregulation of PITX2/IFITM1 cascade is an intrinsic adaptive mechanism during the pathogenesis of letrozole-resistance, and modulation of PITX2/IFITM1 level using different genetic and pharmacological means would thus have a novel therapeutic potential against letrozole resistance in BCa.

Genotype-phenotype analysis in Peters' anomaly patients with PITX2 and PAX6 genes / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To analyze the clinical characteristics of patients with Peters' anomaly(PA)in Chinese, and to study the variation of PITX2 and PAX6 genes in patients with PA, so as to provide basis for clinical diagnosis and pathogenesis of this rare ophthalmopathy.<p>METHODS: Fifteen patients with PA were selected from 2016 to 2019 in Changzhou No. 2 People's Hospital and Changzhou No. 3 People's Hospital, and the detailed clinical data were collected. Genomic DNA was prepared from venous leukocytes after obtaining the consent of the patients and their family members. The coding regions and the flanking exon-intron junctions of the PITX2 and PAX6 genes were amplified by polymerase-chain reaction(PCR)and subsequently analyzed by direct sequencing. Variations detected were further evaluated in any unaffected member and 80 normal controls by HA-SSCP. Analyzing and comparing the mutation of PITX2 and PAX6 genes and the related phenotypes in Chinese patients with PA.<p>RESULTS:Sequence analysis of the PITX2 gene revealed one novel mutation c.296delG(P.R99fsx56)in fifteen patients with PA. Nucleotide sequence analysis showed that this mutation led to the functional abnormal of this gene. The clinical characteristics of the mutant patient were analyzed, the right eye of the patient was diagnosed as Axenfeld-Rieger syndrome(ARS), and the left eye was diagnosed as Peters'anomaly. However, the mutation was not found in the family members of the patient's parents and unrelated normal controls, and therefore it was a de novo mutation. No mutation was found in PAX6 gene mutation screening.<p>CONCLUSION: A novel PITX2 gene mutation was detected in 15 patients with PA, which was the first report of PITX2 gene mutation in a patient with Peters'anomaly complicated with ARS in China. The results enrich the mutation spectrum of PITX2 gene and further clarify the clinical characteristics of PA complicated with ARS. All these will be useful foundations for clinical diagnosis and pathogenesis. Furthermore, it enriches our knowledge of genotype-phenotype relationship of PA. In addition, our results may provide basis for the functional and genomic study of the pathogenesis of the disease in the future.

Rs17042171 at chromosome 4q25 is associated with atrial fibrillation in the Chinese Han population from the central plains / 中南大学学报(医学版)

Objective:To determine the correlations of single nucleotide polymorphisms (SNPs) with atrial fibrillation (AF) in the Chinese Han population from the central plains.Methods:A total of 168 hospitalized patients,including 56 AF and 112 controls,were recruited in this case-control study.The clinical data were obtained from the medical records.All 5 SNPs,rs337711 in KCNN2,rs11264280 near KCNN3,rs17042171 near PITX2,rs6771157 and rs6795970 in SCN10A,were genotyped using amplification refractory mutation system-polymerase chain reaction or direct sequencing.The x2 test was used to compare categorical variables and preliminarily examine correlations between the genotype frequencies and AF.Subsequently,a logistic regression model was constructed to determine the associations between the SNPs and AF based on the above screened results.Odds ratios (ORs) and 95％ confidence interval (CI) were calculated to assess the strength of the correlations.Moreover,we downloaded the genotype data from the HapMap Project for linkage disequilibrium analysis ofrs17042171.Results:AF patients were likely to be of older age and longer left atrial diameter and had more coronary artery disease and higher hypertension compared with the control group (P＜0.05).Among the 5 SNPs,the frequency distribution of genotype AA for rs17042171 was significantly different between the AF and control groups (P＜0.05).After adjusting for several covariates,there was still a high risk ratio in patients with the AA genotype compared with the AC+CC genotype (OR:5.591,95％CI 2.176 to 14.365,P-B＜0.008).Similarly,stratification analysis on the AA genotype demonstrated significant differences between rs17042171 and persistent AF.However,there were not significant correlations between AF and the control groups for the other 4 SNPs (P＜0.05).Conclusion:Rs17042171,near PITX2 on chromosome 4q25,is associated with AF susceptibility in the Chinese Han population from the central plains,suggesting that this SNP can provide a new strategy for clinical diagnosis in AF patients.

Polymorphism analysis of exons 2 and 5 of PITX2 gene of neonatal intestinal malrotation / 中华实用儿科临床杂志

Objective To screen the neonatal malrotation with PITX2 gene exon 2 and 5 gene mutation through the study on molecular genetics.Methods From January 201 2 to December 201 4,1 5 cases of neonatal malro-tation infants(experimental group)and 25 healthy newborn infants(healthy control group)were selected as the research subjects from the First Affiliated Hospital of Shihezi University Medical College.The experimental group included 1 5 ca-ses of volvulus,4 cases of volvulus with duodenal atresia and 3 cases of volvulus with jejunal atresia.The clinical fea-tures were recorded and 3 mL peripheral venous blood from each subject was collected.After ethylenediamine tetraacetic acid (EDTA)anticoagulation,genomic DNA was extracted.Polymerase chain reaction (PCR)was used to amplify the exon 2 and exon 5 of PITX2 gene,and the direct sequencing method was used to screen whether there were mutations in these 2 loci.Results According to the findings of the matching gene,PITX2 gene exon 2 and exon 5 mutations were not detected in 15 cases with intestinal malrotation of the experimental group and 25 healthy newborns in the healthy control group.Conclusions Polymorphisms is not detected in PITX2 gene exon 2 and exon 5 in small groups of newborn,but this does not exclude the possibility the gene caused newborns suffering from intestinal malrotation by other means.

PITX2C loss-of-function mutations responsible for idiopathic atrial fibrillation

OBJECTIVE: This study aimed to identify novel PITX2c mutations responsible for idiopathic atrial fibrillation. METHODS: A cohort of 210 unrelated patients with idiopathic atrial fibrillation and 200 unrelated, ethnically matched healthy individuals used as controls were recruited. The whole coding exons and splice junctions of the PITX2c gene, which encodes a paired-like homeobox transcription factor required for normal cardiovascular morphogenesis, were sequenced in 210 patients and 200 control subjects. The causative potentials of the identified mutations were automatically predicted by MutationTaster and PolyPhen-2. The functional characteristics of the PITX2c mutations were explored using a dual-luciferase reporter assay system. RESULTS: Two novel heterozygous PITX2c mutations (p.Q105L and p.R122C) were identified in 2 of the 210 unrelated patients with idiopathic atrial fibrillation. These missense mutations were absent in the 400 control chromosomes and were both predicted to be pathogenic. Multiple alignments of PITX2c protein sequences across various species showed that the altered amino acids were highly evolutionarily conserved. A functional analysis demonstrated that the mutant PITX2c proteins were both associated with significantly reduced transcriptional activity compared with their wild-type counterparts. CONCLUSION: The findings of this study associate PITX2c loss-of-function mutations with atrial fibrillation, supporting the hypothesis that dysfunctional PITX2c confers enhanced susceptibility to atrial fibrillation and suggesting potential implications for early prophylaxis and allele-specific therapy for this common arrhythmia. .

Molecular mechanism and regulation in the formation of dextrocardia / 国际儿科学杂志

Dextrocardia is formed by the disruption of the normal left-right (L-R) asymmetry of the thoracoabdominal organs.Asymmetric expression of Nodal,Pitx2,Cited2 have affected L-R asymmetry of vertebrate significantly,and generated dextrocardia,mesocardia,ectopia cordis,heterotaxy and so on.Dextrocardia is often accompanied by congenital cardiac malformation.Therefore,it is so difficult to be treated that it has poor prognosis.This paper reveiws the molecular mechanism and it's regulation of dextrocardia for proceeding the genetic diagnosis and early intervention of dextrocardia sequentially in order to improve the survival rate and life quality of patients.

Novel c.300_301delinsT Mutation in PITX2 in a Korean Family with Axenfeld-Rieger Syndrome

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 Korea.

Anomalous Scleral Insertion of Superior Oblique in Axenfeld-Rieger Syndrome

Axenfeld-Rieger syndrome (ARS) is associated with ocular and systemic anomalies. PITX2 is known to be a major controlling gene in the pathogenesis of ARS and is associated with differentiation in both the neural crest and mesoderm during eye development. A 4-year-old girl with bilateral ARS had 20 prism diopters (PD) of exotropia with 30PD of A- pattern deviation, more than 20PD of dissociated vertical deviation (DVD), and severe superior oblique overaction (SOOA). During surgery we observed that the SO inserted more posteriorly than normal. We believe this finding is one of the abnormal manifestations of the development of the extraocular muscles in ARS.

Role of PITX2 R62H Mutation in Ring Dermoid of Cornea / 生物化学与生物物理进展

Ring dermoid of cornea (RDC) is an autosomal dominant disorder of cornea. The previous study identified a G185A mutation of PITX2 gene in a Chinese family with RDC. To investigate the pathological mechanism of PITX2 R62H mutation, a PITX2 prokaryotic expression plasmid were constructed and GST-PITX2 fusion protein were purified. EMSA was further conducted. The DNA-banding ability of PITX2 R62H was similar to that of the wild type PITX2 were found. The cell lines stably expressed PITX2 was also generated, and cell cycle were analyzed by flow cytometry, and the expression of ?-catenin and Cyclin D1 were detected by quantitative Real-time PCR. The results showed that proliferating ability of cells expressing PITX2 R62H was lower than that of cells expressing PITX2 WT, as well as ?-catenin and Cyclin D1 mRNA level. These findings revealed that PITX2 R62H mutation affected the Wnt/?-catenin→PITX2 pathway, promoted the genes expressing abnormally, and led to abnormal cell proliferation and the formation of RDC, which may play an important role in pathogenesis of RDC.