A novel mutation in PAX6 gene causing congenital iris coloboma with congenital cataract in a pedigree / 中华实验眼科杂志

Objective:To identify the pathogenic gene and inheritance pattern in a pedigree of congenital iris coloboma with congenital cataract.Methods:The method of pedigree investigation was adopted.A pedigree of congenital iris coloboma with congenital cataract was collected by Yunnan Disabled Rehabilitation Center and the 2nd Afliated Hospital of Kunming Medical University in February 2020.Ophthalmic examinations were carried out on the female proband, her parents, her children and her husband, and the clinical diagnosis was made.Genomic DNA was extracted from peripheral blood samples collected from the family members.The suspected pathogenic gene in the proband and her husband was screened by whole exome sequencing and was identified by bioinformatics analysis.The amino acid conservation was analyzed by UGENE software.The impact of the mutation on protein translation was predicted using MutationTaster software.The pathogenicity of the mutation was assessed according to the American College of Medical Genetics (ACMG) Standards and Guidelines.Pathogenic gene and mutations were verified by Sanger sequencing.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of the 2nd Afliated Hospital of Kunming Medical University (No.PJ-2020-61).Written informed consent was obtained from each subject or custodian.Results:The proband showed large iris defects in both eyes with only a small amount of observable iris tissue in the periphery, lens cortical opacity and posterior capsule opacification, accompanied by nystagmus.A novel heterozygous frameshift variation c. 415dupA (p.R139fs) was located in exon 8 of PAX6 gene, and the variation was conservative across multiple species.The variation was in the highly conserved region of PAX6 gene and caused the dysfunction of PAX6 protein.The variation was graded as PVS1+ PM2+ PP1, a pathogenic variation, based on ACMG guidelines.The pedigree was consistent with co-segregation, indicating that the novel variation was pathogenic.The proband and her children were diagnosed, but her parents were phenotypically normal, in accordance with autosomal dominant inheritance. Conclusions:The novel frameshift variation c.415dupA (p.R139fs) on the exon 8 of PAX6 gene is responsible for congenital iris coloboma with congenital cataract in the pedigree.This is the first report of this novel variation in PAX6 gene.

Ophthalmological evaluation and integrated intervention in a family with congenital aniridia in Alagoas, Brazil / Avaliação oftalmológica e intervenção integrada em família com aniridia congênita em Alagoas, Brasil

Abstract Objective: We aimed to describe the clinical and phenotypic manifestations as well as the visual prognosis of a family with CA in Northeastern Brazil. Methods: This was a cross-sectional study involving 31 individuals (56 eyes) from the same family presenting CA phenotypes. The study population resided in the municipality of Água Branca, in the backlands of the state of Alagoas, Northeastern Brazil. The clinical and phenotypic variables were analyzed. For the analysis, descriptive statistics (absolute and relative frequency and measures of central tendency and dispersion) and inferential statistics (Shapiro-Wilk and Student's t tests) were used, with 95% confidence intervals and significance set at 5%. Results: Of the 31 individuals, 18 (58.1%) were male, with a mean age of 27.45 ± 17.49 years, with no difference between sexes. Of the 56 eyes evaluated, 26 and 30 were right and left eyes, respectively; 61.3% (n = 19) individuals had complete bilateral aniridia and 25.8% (n = 8) reported a total loss of light perception in both the eyes. The most prevalent ocular abnormalities were nystagmus (n = 27; 87.09%), cataract (n = 20; 64.5%), strabismus (n = 14; 45.2%), corneal changes such as opacities and/or vascularization (n = 13; 41.93%), and ectopia lentis (n = 6; 19.4%). Further, 13 individuals underwent retinal optical coherence tomography, six man and seven women aged 9-48 (mean, 30.15 ± 15.9) years. All patients presented absence of foveal depression as well as reduced macular thickness and visual acuity. Nine subjects underwent phacoemulsification. Conclusion: The study showed wide phenotypic variation among the studied individuals, with poor visual prognosis. The study highlights the need to establish comprehensive care mechanisms for families with the disease.

Resumo Objetivo: Descrever manifestações clínicas e fenotípicas e o prognóstico visual de uma família com aniridia congênita (AC). Métodos: Trata-se de estudo transversal envolvendo 31 indivíduos (56 olhos), de uma mesma família com fenótipo de AC residindo no município de Água Branca, no sertão do estado de Alagoas, região nordeste do Brasil. Foram analisadas variáveis clínicas e fenotípicas. Para a análise, foi utilizada a estatística descritiva (frequência absoluta e relativa e medidas de tendência central e de dispersão) e inferencial (testes de Shapiro-Wilk e t Student). Considerou-se o intervalo de confiança de 95% e a significância de 5%. Resultados: Dos 31 indivíduos, 18 (58,1%) eram do sexo masculino, com média de idade de 27,45±17,49, sem diferença entre os sexos. Dos 56 olhos avaliados, 26 eram olhos direitos e 30 olhos esquerdos: 61,3% (n=19) apresentavam aniridia bilateral total; 25,8% (n=8) referiam perda total de percepção da luz em ambos os olhos. As anormalidades oculares mais prevalentes foram o nistagmo (n=27; 87,09%), catarata (n=20; 64,5%), estrabismo 14 (45,2%), alterações opacidades ou vascularização corneanas (n=13; 41,93%) e ectopia lentis (n=6; 19,4%). Os 13 indivíduos submetidos à tomografia de coerência óptica (OCT) retiniana apresentavam perda da depressão foveal, redução da espessura macular e redução da acuidade visual. Nove indivíduos foram submetidos a cirurgia de facoemulsificação. Conclusão: O estudo mostrou ampla variação fenotípica entre os indivíduos estudados, com pobre prognóstico visual. O estudo destaca a necessidade de estabelecer mecanismos de cuidado integral para as famílias com a doença.

Genetic screening of the congenital aniridia and genotype-phenotype analysis / 中华实验眼科杂志

Objective@#To explore the genotype-phenotype correlation among 3 pedigrees affected with congenital aniridia.@*Methods@#Clinical data and genomic DNA were collected and genetic variations were screened by whole-exome sequencing, with an emphasis on PAX6-related genes.Suspected variations were verified by Sanger sequencing and quantitative polymerase chain reaction (PCR). Written informed consent was obtained from the parents of each propositus prior to entering study cohort.This study protocol was approved by Ethic Committee of Henan Eye Hospital (No.HNEECKY-2017(6)).@*Results@#Genetic analysis identified that a nonsense c. 949 C>T variation and an c. 141+ 1 G>T splicing variation of the PAX6 gene in two of the probands, while the remainder has carried a duplication in 11 p13 (chr11: 31531331-31827959) encompassing the PAX6 and ELP4 genes.Phenotype analysis showed that the probands carrying the nonsense and splicing variations had classical features including complete aniridia, macular hypoplasia, microcornea and nystagmus; the proband carrying the 11p13 duplication had microphthalmos, microcornea, macular dysplasia, iris dysgenesis, and nystagmus.@*Conclusions@#The 11p13 duplication involving the PAX6 gene may have caused over-expression of PAX6 gene, resulting in severe eye abnormalities including microphthalmos and microcornea, macular dysplasia and nystagmus.The relatively mild iris dysgenesis has distinguishing it from classical aniridia due to PAX6 haploinsufficiency.

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.

Mutation analysis of a family affected with congenital aniridia and congenital cataract / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To identify the potential mutation in a Chinese family affected with congenital aniridia and cataract, which can expands the mutation spectrum of antosomal dominant congenital aniridia.<p>METHODS: A Chinese family with congenital aniridia and cataract and 100 unrelated controls were recruited, peripheral venous blood was collected for genomic DNA extraction. Candidate genes sequencing was performed by direct DNA sequencing to screen out the <i>PAX6 </i>mutation.<p>RESULTS: All affected individuals in the family showed aniridia and cataract. A novel non-sense mutation c.991 C>T in exon 11 of <i>PAX6</i> was exclusively observed in all affected individuals but not in any of the unaffected family members or unrelated controls, which results in the truncation of encoding protein(R331X). <p>CONCLUSION: We identified a novel mutation in the <i>PAX6</i> R331X, which may be responsible for the pathogenesis of congenital aniridia and cataract.

Disease genes detection of two anterior segment dysgenesis pedigree by whole exome sequence / 眼科新进展

Objective To identify the disease-causing gene mutation in families with anterior segment dysgenesis (ASD).Methods Two ASD families coming from Henan and Hebei provinces were enrolled in this study.Ocular examinations were performed,and periphery blood specimens were collected from each family member under the informed consent.The blood samples of 2 patients and 1 normal person in family 1 and 1 patient and 1 normal person in family 2 were analyzed by the whole exome sequences.The candidate genes were verified by Sanger sequence and predicted damages by PolyPhen-2 and SIFT Human Splicing Finder software.Results Family 1 including 9 patients were examined in serial 3 passages,which conformed to autosomal dominant inheritance pattern.Clinical examination revealed binocular anterior segment dysgenesis in the 9 patients.There were 13 SNV and 55 InDel candidate mutations.And missense mutation c.T2A(p.M1K)on PAX6 gene was found.Family 2 included 8 members,and 2 patients were examined.The splicing mutation c.357 + 1g ＞ c on the same gene was found.Conclusion T2A(p.M1 K) and c.357 + 1 g ＞ c mutations in PAX6 gene are responsible for ASD.Whole exome sequence provides a new approach to detect diseasecausing mutation of ASD with diversity clinical phenotypes.

Mutation analysis of Pax6 in Chinese patients with congenital aniridia / 中华实验眼科杂志

Background Congenital aniridia is a rare congenital autosomal dominant disease,which is shown as aniridia of double eyes,and the paired box gene 6 (Pax6) gene mutation is now known to be associated with congenital aniridia.Objective This study was to screen the Pax6 gene mutation in patients with congenital aniridia.Methods Eleven patients with congenital aniridia were enrolled in Tianjin Eye Hospital from August 2012 to October 2015,including 6 patients from 3 congenital aniridia family and 5 sporadic patients.All patients received routine ophthalmic examination.Peripheral venous blood of 3 ml was collected from the patients for DNA extraction according to the standard process of DNA isolation instructions,and all the exons of Pax6 gene,Elp4 gene,exon 5 ' and 3',intron splice sequence and SIMO sequence were amplified by PCR.Pax6 genes of the patients were sequenced using Sanger direct sequencing and multiplex ligation dependent probe amplification (MLPA) and compared with those of 500 ocular trauma patients.This study complied with Helsinki declaration,and written informed consent was obtained from each patient prior to any medical examination.Results Iris absence was found in all the patients,and the visions acuity was hand motion to 0.2.Lens dislocation was seen in 1 patient.Direct sequencing results found that three patients in AN-O1 family were c.688g＞t (p.E230X) mutation of Pax6 gene,and 3 of 5 sporadic patients carried c.468g＞a (p.W156X),c.613c＞t (p.Q205X) and c.141 +2t＞c mutant of Pax6 gene,and the c.688g＞t (pE230X) mutation was a novel-discovered mutation.No any mutation in Pax6,Elp4 gene and SIMO fragment was detected in 1 patient from AN-02 family,2 patients from AN-03 family and 2 sporadic patients by both direct sequencing and MLPA validation.No above-mentioned mutation was found in 500 normal individuals.Conclusions The mutation of Pax6 gene is a pathogenic mutation in congenital aniridia patients,and c.688g＞t (p.E230X) is a novel Pax6 mutant,which expanded the mutation spectrum of Pax6 gene.

Research progress of the association between PAX6 gene and retinal diseases / 国际眼科杂志(Guoji Yanke Zazhi)

PAX6 gene plays an important role in embryological development, and the mutation of this gene may result incongenital aniridia, retinoblastoma, macula hypoplasia, Peters' anomaly and so on. A brief introduction of the background PAX6 gene, and the association between PAX6 and retinal diseases were summarized in this review.

Absence of mutations in Pax6 gene in three cases of Morning Glory syndrome associated with isolated growth hormone deficiency / A ausência de mutações no gene PAX6 em três casos de síndrome de Morning Glory associada à deficiência isolada de hormônio do crescimento

Morning glory syndrome (MGS) is a congenital optic disc dysplasia often associated with craniofacial anomalies, especially basal encephalocele and hypopituitarism. Clinical signs are varied and often occult. The PAX6 gene is involved in ocular morphogenesis and is expressed in numerous ocular tissues during development especially in the developing central nervous system. The aim of the present study is to evaluate PAX6 in MGS associated with isolated growth hormone deficiency. Three pre-pubertal males (A, B and C) with MGS and short stature due to growth hormone deficiency, treated with recombinant human growth hormone with limited response, were reported. Two of them had basal encephalocele. Coding and non-coding sequences corresponding of PAX6 different transcripts were analyzed by direct sequencing. Nucleotide variations causing putative aminoacid change were not observed. Patient A presented the new IVS2+9G>A transition, whereas patients A and C were heterozygous for known single nucleotide polymorphisms (SNP) within the intron 4. In addition, two SNP heterozygoses were observed for patient C in both intron 9 and 13. Sequencing also revealed several nucleotide variations in patient B. Two heterozygoses for known polymorphisms were identified along with a novel C>A nucleotide change in intron 4. This patient also presented a low number on the TG repeat in intron 9 and a new IVS11+33A>T transversion. Gene regulation and transcription of PAX6 are complex processes; there are two major protein isoforms, PAX6(-5a) and PAX6(+5a), and nine transcripts described. Furthermore, extra transcription regulatory elements have been postulated within PAX6 introns. Considering that neither population distributions on PAX6 polymorphism nor their linkeages with diseases have been reported, a functional effect due to alterations described here cannot be discarded.

A síndrome de Morning Glory (SMG) é uma displasia óptica congênita associada a anomalias craniofaciais, principalmente encefalocele basal e hipopituitarismo. Os sinais clínicos são variados e muitas vezes ocultos. O gene PAX6 está envolvido na morfogênese ocular e se expressa em vários tecidos oculares durante o desenvolvimento do sistema nervoso central. O objetivo deste estudo foi avaliar o gene PAX6 na SMG associada com deficiência isolada de hormônio de crescimento. Foram relatados três pacientes pré-púberes (A, B e C) com SMG e baixa estatura por deficiência de hormônio de crescimento tratados com hormônio de crescimento recombinante humano. As seqüências codificadoras e não-codificadoras correspondentes ao PAX6 em diferentes transcritos foram analisadas por seqüenciamento direto. Variações nucleotídeas com trocas pontuais de aminoácidos não foram encontradas. O paciente A apresentou uma transição nova IVS2+9G>A, enquanto os pacientes A e C foram heterozigotos para um polimorfismo (SNP) no íntron 4. Ainda, dois SNPs em heterozigose nos íntrons 9 e 13 foram observados no paciente C. O seqüenciamento também mostrou várias variações nucleotídeas no paciente B. Dois SNPs conhecidos com a alteração nucleotídea nova C>A no íntron 4 foram observados em heterozigose. Este paciente também apresentou um baixo número de repetições TG no íntron 9 e uma nova transversão IVS11+33A>T. A regulação e a transcrição do gene PAX6 são um processo complexo; existem 2 isoformas principais da proteína, PAX6(-5a) e PAX6(+5a) e 9 transcritos descritos. Considerando que nem a distribuição de SNPs no PAX6 e nem as suas ligações com as doenças foram relatadas, um defeito funcional devido às alterações descritas não pode ser descartado.

PAX6 Mutations and Clinical Features of Congenital Aniridia

PURPOSE: To report the PAX6 mutations and clinical features in Korean aniridia patients. METHODS: Genomic DNA was isolated from 12 aniridia patients and 5 normal controls. The coding regions of the PAX6 gene were analyzed by direct sequencing of polymerase chain reaction products. The relationship between the mutational types and the ophthalmic findings from medical records was determined. RESULTS: Mutation analysis demonstrated seven different types of mutations, five of which have not previously been reported. Notably, these mutations were confined to PD and LNK in the PAX6 gene. Although R44X and W156X were recurrent mutations, novel mutations included G18R, IVS6+1insG, A139P, A139A, and G141G. Glaucoma was found in five (42%, adult patients 30 years or older) of twelve patients, of whom four were male. CONCLUSIONS: This is the first report to identify the PAX6 gene mutations in Korean aniridia patients. Our limited data show that glaucoma was more prevalent in male and adult patients. Moreover, a patient's age along with the PAX6 genotype might be a factor related to glaucoma in aniridia patients.