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.

Expression of Pax6 and Pax7 proteins during the central nervous system development in human embryos / Expresión de proteínas Pax6 y Pax7 durante el desarrollo del sistema central nervioso en embriones humanos

The family of paired box (Pax) genes encodes the transcription factors that have been emphasized for the particular importance to embryonic development of the CNS, with the evidence obtained from various animal models. Human embryos have rarely been available for the detection of the expression of Pax family members. In this study 32 human embryos of Carnegie (CS) stages 10-20 were investigated to find the differences in the expression of Pax6 and Pax7 proteins in different regions of the neural tube and the caudal spinal cord. The expression of Pax6 and Pax7, as determined by immunohistochemistry, showed a tendency to increase in the later stages of the development both in the spinal cord and the brain. Significantly weaker expression of Pax6 and Pax7 was observed at CS 10 as compared to the later stages. At CS 10-12 weak expression of Pax6 was noticed in both dorsal and ventral parts of the developing spinal cord, while the expression of Pax7 was restricted to the cells in the roof plate and the dorsal part of the spinal cord. At CS 14-20 in the developing spinal cord Pax6 and Pax7 were detected mostly in the neuroepithelial cells of the ventricular layer, while only weak expression characterized the mantle and the marginal layers. At the same stages in the developing brain Pax6 and Pax7 were expressed in the different regions of the forebrain, the midbrain and the hindbrain suggesting for their involvement in the differentiation of neurons in specific parts of the developing brain.

La familia de genes Pax del inglés (Paired box) codifica los factores de transcripción debido a la particular importancia en el desarrollo embrionario del SNC, con la evidencia obtenida de varios modelos animales. Rara vez han estado disponibles embriones humanos para la detección de la expresión de genes de la familia Pax. En este estudio, se investigaron 32 embriones humanos de Carnegie (CS) etapas 10-20 para encontrar las diferencias en la expresión de las proteínas Pax6 y Pax7 en diferentes regiones del tubo neural y la médula espinal caudal. La expresión de Pax6 y Pax7, según la inmunohistoquímica, se observó una tendencia a aumentar en las etapas posteriores del desarrollo, tanto en la médula espinal como en el cerebro. Se observó una expresión significativamente más débil de Pax6 y Pax7 en CS 10 en comparación con las etapas posteriores. En CS 10-12 se notó una expresión débil de Pax6 en las partes dorsal y ventral de la médula espinal en desarrollo, mientras que la expresión de Pax7 se limitó a células en la placa del techo y dorsal de la médula espinal. En CS 14-20 en la médula espinal en desarrollo, Pax6 y Pax7 se observó principalmente en las células neuroepiteliales de la capa ventricular, mientras que expresión débil se caracterizó en las capas marginales. En las mismas etapas en el cerebro en desarrollo, Pax6 y Pax7 se expresaron en las diferentes áreas del prosencéfalo, el mesencéfalo y el mesencéfalo, lo que sugiere su participación en la diferenciación de las neuronas en partes específicas del cerebro en desarrollo.

Identification of a novel PAX6 mutation in a sporadic case with congenital aniridia / 中华医学遗传学杂志

OBJECTIVE@#To identify mutation of the PAX6 gene in a patient with congenital aniridia.@*METHODS@#DNA was extracted from peripheral blood sample of the patient and analyzed by direct PCR-Sanger sequencing.@*RESULTS@#The proband was found to harbor a heterozygous c.239T>A (p.Ile80Asn) mutation of the PAX6 gene. The same mutation was not found in his parents and 150 healthy controls.@*CONCLUSION@#A novel mutation of the PAX6 gene has been identified in a sporadic case with congenital aniridia.

Recapitulating cortical development with organoid culture in vitro and modeling abnormal spindle-like (ASPM related primary) microcephaly disease

The development of a cerebral organoid culture in vitro offers an opportunity to generate human brain-like organs to investigate mechanisms of human disease that are specific to the neurogenesis of radial glial (RG) and outer radial glial (oRG) cells in the ventricular zone (VZ) and subventricular zone (SVZ) of the developing neocortex. Modeling neuronal progenitors and the organization that produces mature subcortical neuron subtypes during early stages of development is essential for studying human brain developmental diseases. Several previous efforts have shown to grow neural organoid in culture dishes successfully, however we demonstrate a new paradigm that recapitulates neocortical development process with VZ, OSVZ formation and the lamination organization of cortical layer structure. In addition, using patient-specific induced pluripotent stem cells (iPSCs) with dysfunction of the Aspm gene from a primary microcephaly patient, we demonstrate neurogenesis defects result in defective neuronal activity in patient organoids, suggesting a new strategy to study human developmental diseases in central nerve system.

Analysis of PAX6 gene mutation in a family affected with congenital aniridia / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To identify potential mutation of the PAX6 gene in a family affected with congenital aniridia from northeastern China.</p><p><b>METHODS</b>Two patients were collected from the family and underwent full ophthalmologic examinations. Genomic DNA was extracted from all family numbers and 100 healthy controls. The coding regions and flanking sequence of the PAX6 gene were amplified by PCR amplification and subjected to bidirectional DNA sequencing.</p><p><b>RESULTS</b>A nonsense mutation (c.718 C>T) was identified in exon 9 in both patients but not in other unaffected families or the 100 healthy controls. However, obvious difference was noted in the phenotype between the two patients. One of the patient has presented irregular cornea, which was infrequently reported.</p><p><b>CONCLUSION</b>A c.718C>T transitional mutation has been found to underlie the aniridia, which showed an autosomal dominant inheritance pattern in this northeastern Chinese family.</p>

Analysis of PAX6 gene mutations in a Chinese family affected with congenital aniridia / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the mutation of PAX6 gene in a Chinese family affected with congenital aniridia.</p><p><b>METHODS</b>Blood samples were drawn from family members, and DNA was analyzed by direct sequencing.</p><p><b>RESULTS</b>A heterozygous mutation (c.151 G>A) was identified in the PAX6 gene in the proband and other patients from the family. The same mutation was not found among unaffected family members and 160 unrelated healthy controls.</p><p><b>CONCLUSION</b>A novel mutation in the PAX6 gene has been identified in a Chinese family affected with aniridia.</p>

The homeodomain of Eyeless regulates cell growth and antagonizes the paired domain-dependent retinal differentiation function

Pax6 and its Drosophila homolog Eyeless (Ey) play essential roles during eye development. Ey/Pax6 contains two distinct DNA binding domains, a Paired domain (PD) and a Homeodomain (HD). While Ey/Pax6 PD is required for the expression of key regulators of retinal development, relatively little is known about the HD-dependent Ey function. In this study, we used the UAS/GAL4 system to determine the functions of different Ey domains on cell growth and on retinal development. We showed that Ey can promote cell growth, which requires the HD but not the PD. In contrast, the ability of Ey to activate Ato expression and induce ectopic eye formation requires the PD but not the HD. Interestingly, deletion of the HD enhanced Ey-dependent ectopic eye induction while overexpression of the HD only Ey forms antagonizes ectopic eye induction. These studies revealed a novel function of Ey HD on cell growth and a novel antagonistic effect of Ey HD on Ey PD-dependent eye induction. We further show the third helix of the Ey HD can directly interact with the RED subdomain in Ey PD and that deletion of the HD increased the binding of Ey PD to its target. These results suggest that the direct interaction between the HD and the PD potentially mediates their antagonistic effects. Since different Ey splicing forms are expressed in overlapping regions during normal development, we speculate that the expression ratios of the different Ey splice forms potentially contribute to the regulation of growth and differentiation of these tissues.

Identification of a novel PAX6 mutation in a family with congenital aniridia / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To detect potential mutation in a Chinese family where two individuals were affected with hereditary congenital aniridia.</p><p><b>METHODS</b>Peripheral blood samples were taken for genomic DNA extraction. All of the 15 exons of PAX6 gene were amplified with PCR. The product were purified with gel electrophoresis and sequenced.</p><p><b>RESULTS</b>In both patients, a novel deletion mutation (c.957-958delCA) in exon 13 of the PAX6 gene was identified, which has produced a terminator codon. The same mutation was not found in healthy controls.</p><p><b>CONCLUSION</b>A c.957-958delCA mutation of PAX6 gene is probably the cause of aniridia in this Chinese family.</p>

A novel mutation of the PAX6 gene in a Chinese family with aniridia / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>The PAX6 gene encodes a transcriptional regulator involved in oculogenesis and other developmental processes such as aniridia, a congenital condition characterized by the underdevelopment of the iris of eyes. The function of the PAX6 gene in these two conditions is still poorly defined. The purpose of this study is to identify the mutation of the PAX6 gene in a Chinese family with aniridia.</p><p><b>METHODS</b>Two aniridia patients collected from the family underwent full ophthalmologic examination. Genomic DNA was prepared from venous leukocytes of the two patients and five healthy individuals in the family, and 100 unrelated healthycontrols. Exons 4-13 and their immediate flanking sequences of the PAX6 gene was analyzed by PCR amplification, direct sequencing, and single-strand conformation polymorphism(SSCP).</p><p><b>RESULTS</b>The sequencing result revealed a novel PAX6 mutation in the two patients. It was a heterozygous mutation (IVS10+1G>A) at the boundary of exon 10 and intron 10. The mutation was also detected by SSCP analysis. It was not detected in the healthy relatives and unrelated controls.</p><p><b>CONCLUSION</b>Aniridia is an autosomal dominant inheritable disease. A novel PAX6 gene mutation has been identified in the Northeastern Chinese family with aniridia. The genetic analysis suggested that this novel mutation in the PAX6 gene is capable of causing the classic aniridia phenotype.</p>

Mutation analysis of the PAX6 gene in a family with congenital aniridia and cataract / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To identify the mutation in the PAX6 gene in a family with congenital aniridia and cataract.</p><p><b>METHODS</b>Total genomic DNA was extracted from peripheral blood leukocytes of 12 family members including three living affected members and 96 unrelated healthy controls. The coding exons 4-13 of the PAX6 gene with intronic flanking sequences were amplified by polymerase chain reaction (PCR). By comparing sequences of the affected members with that of normal individuals, the disease-causing mutation was detected by direct DNA sequencing.</p><p><b>RESULTS</b>A PAX6 mutation was identified in the 3 patients, which did not exist in the unaffected members and unrelated healthy individuals. The nonsense mutation of C to T was detected at the nucleotide 1143, which converted the Arg codon (CGA) to a stop codon(TGA) (R261X) in exon 10.</p><p><b>CONCLUSION</b>The mutation (R261X) detected in the present study is considered to result in the occurrence of congenital aniridia and cataract in the Chinese family.</p>

R240X mutation of the PAX6 gene in a Chinese family with congenital aniridia / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To study the PAX6 gene mutation in a Chinese pedigree with congenital aniridia.</p><p><b>METHODS</b>Linkage analysis was performed to the Chinese family with congenital aniridia using two microsatellite markers D11S904 and D11S935. Analysis of the PAX6 gene mutation was done by direct sequencing of the whole coding region and exon-intron boundaries of the PAX6 gene in all affected and unaffected individuals in the family.</p><p><b>RESULTS</b>The significant Lod Score of 3.01 was acquired at D11S935. Direct DNA sequence analysis identified a 1080C to T change in exon 9 of the patients, resulting in an Arginine substitution by a stop codon at codon 240 of the PAX6 gene, which was absent in the unaffected individuals in the family and 100 normal controls.</p><p><b>CONCLUSION</b>Our results indicate that mutation p.Arg240Ter of the PAX6 is the genetic basis of the Chinese family with congenital aniridia.</p>

Occurrence of supernumerary upper incisor teeth in Pax6-/- mouse fetuses / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the occurrence of supernumerary upper incisor teeth in Pax6-/- mouse fetuses and to provide a model to explore the role of Pax6 in the upper incisor development and the mechanism of supernumerary teeth involving Pax6.</p><p><b>METHODS</b>Twenty Pax6-/- mouse fetuses of strain DEBA were isolated on E18.5 (embryonic day). The fetuses were sectioned serially in coronal plane and stained with haematoxylin and erosion, then the presence of supernumerary teeth in the upper anterior area was examined histologically, and also the number, morphology and structure of lower incisor germs and the first and second molar germs in the maxilla and mandible were observed histologically. Eighteen E18.5 mouse fetuses of strain DEBA with Pax6+/+ genotype were used as control.</p><p><b>RESULTS</b>Of the 20 Pax6-/- fetuses examined, four possessed a single supernumerary tooth in the upper incisors' region. No supernumerary upper incisor teeth were observed in any of the 18 Pax6+/+ fetuses examined. In the regions of lower incisors and the first and second molars of the maxilla and mandible, no significant difference was observed between Pax6-/- and Pax6+/+ fetuses regarding the number, morphology and structure of tooth germs.</p><p><b>CONCLUSIONS</b>The results suggest that Pax6 played an important role in the development of upper incisor teeth in mice.</p>

A novel mutation of the PAX6 gene identified in a northeastern Chinese family with congenital aniridia / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To identify the mutation of the PAX6 gene in a northeastern Chinese family with aniridia.</p><p><b>METHODS</b>Three aniridia patients from the family were undergone full ophthalmologic examinations. Genomic DNA was prepared from venous leukocytes from these three patients, five non-carriers in the family as well as 100 healthy normal controls. The coding regions of PAX6 gene were analyzed by PCR amplification, single-strand conformation polymorphism and direct DNA sequencing.</p><p><b>RESULTS</b>The sequencing result revealed one novel PAX6 mutation in the three patients with familial aniridia. The mutation is a 9 base pair(bp) deletion in exon 5 (c.483del9) that results in a putative PAX6 protein with in-frame deletions of aspartic acid, isoleucine and serine at the amino acids 41-43.</p><p><b>CONCLUSION</b>A PAX6 gene mutation beyond the existing spectrum of mutations has been identified in a northeastern Chinese family with aniridia. The genetic analysis suggests that the novel mutation in the PAX6 gene may be the cause of the classical aniridia phenotype.</p>

Mutation analysis of PAX6 gene in a large Chinese family with aniridia / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Mutations in PAX6 gene have been shown to be the genetic cause of aniridia, which is a severe panocular eye disease characterised by iris hypoplasia. However, there is no study to do genetic analysis of aniridia, although there are several case reports in China. Here, we describe a mutation analysis of PAX6 in a large Chinese family with aniridia.</p><p><b>METHODS</b>Genomic DNA from venous blood samples was prepared. Haplotype analysis was performed with two genetic markers (D11S904 and D11S935). Fourteen exons of the PAX6 gene were amplified from genomic DNA. Polymerase chain reaction (PCR) products of each exon were analysed by single strand conformational polymorphism (SSCP). The PCR products having an abnormal pattern were sequenced to confirm the mutation.</p><p><b>RESULTS</b>Significant evidence for allele sharing in affected patients was detected suggesting that PAX6 mutation links to aniridia in this family. An extra band corresponding to exon 9 in PAX6 was found by single strand conformational polymorphism analysis in all the aniridia patients in this family, but not detected in the unaffected members. A mutation of C to T was detected by sequencing at the nucleotide 1080 that converts the Arg codon (CGA) to the termination codon (TGA).</p><p><b>CONCLUSIONS</b>Aniridia is caused by a nonsense mutation of PAX6 gene in the large Chinese kindred. Genetic test is important to prevent the transmission of aniridia to their offsprings in the kindred by prenatal diagnosis.</p>

Expression of pax-6 in rhesus monkey of optical defocus induced myopia and form deprivation myopia / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Pax-6 gene plays an important role in the process of eye development. This study was to determine the role of pax-6 in the axial myopia produced by hyperopic optical defocus and form deprivation in infant monkeys.</p><p><b>METHODS</b>Among seven normal infant rhesus monkeys (aged 1 to 1.5 months), five wore -3.00 D spectacle lenses over their right eyes and zero-powered lenses over their left eyes. Monocular form deprivation was produced by eyelid fusion in two monkeys. Ten weeks later, the monkeys were sacrificed by an overdose of barbiturates and their eyes were removed immediately. A 5 mm x 5 mm button of retina and sclera was taken from the posterior poles along with a 4-mm optic nerve. RNA was isolated separately from each of these three types of tissues. After that, reverse transcription polymerase chain reaction (RT-PCR) was used for determining gene expression in the retina, sclera and optic nerve. Semi-quantitative analyses were performed on the PCR products.</p><p><b>RESULTS</b>As expected, the optically induced hyperopic defocus and the form deprivation produced myopic growth. For the lens-treatment monkeys, pax-6 gene expression in the retinas of the defocused eyes was significantly higher than in the retinas of the left eyes (t = 5.703, P = 0.005). However, there were no analogous significant differences between pax-6 expression in the scleras or the optic nerves. For the two form-deprived monkeys, there were no obvious differences in pax-6 gene expression in the retinas or the optic nerves.</p><p><b>CONCLUSION</b>The result that the expression of pax-6 was enhanced by hyperopic defocus in the infant monkey retina suggests that pax-6 may be involved in vision-dependent eye growth and emmetropization.</p>