Novel PAX6 mutation reported in an aniridia patient.
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ABSTRACT:
SUBMITTER: Winegarner A
PROVIDER: S-EPMC5719187 | biostudies-other | 2017
REPOSITORIES: biostudies-other
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Project description:BACKGROUND:Congenital aniridia is a severe ocular abnormality characterized by incomplete formation of the iris and many other ocular complications. Most cases are caused by the paired box 6 (PAX6) gene mutations generating premature termination codons (PTCs). METHODS:Ophthalmic examination was performed on a Chinese pedigree with congenital aniridia. The mutation was identified by targeted next-generation sequencing. Nonsense suppression therapy was applied on patient-derived lymphocytes. The PAX6 expression was assayed by real-time polymerase chain reaction and Western blot. RESULTS:Complete aniridia was complicated with horizontal nystagmus, contract, foveal hypoplasia, and microphthalmia. A novel heterozygous c.702_703delinsAT (p.Tyr234*) mutation was found in exon 9 of PAX6, generating a PTC at the homeodomain. There were about 50% reductions of both full-length PAX6 protein and PAX6 mRNA in patient-derived lymphocytes, indicating haploinsufficiency due to nonsense-mediated mRNA decay. Ataluren (PTC124) and geneticin (G418) could induce about 30%-40% translational readthrough. Nonsense suppression therapy restored PAX6 protein to about 65%-70% of unaffected family controls. CONCLUSION:Our data expanded the genetic and phenotypic variations of congenital aniridia, and showed the therapeutic effect of nonsense suppression on this disease using patient-derived cells.
| S-EPMC7216799 | biostudies-literature
Project description:The present study investigated the clinical and mutational spectrum of aniridia in a cohort of 17 affected individuals from six families from Cyprus. Each proband was initially evaluated for copy number variants at the PAX6 locus and subsequently underwent PAX6 mutation screening. Sequence analysis of FOXC1 and PITX2 was performed in patients who did not carry a PAX6 mutation. The most common clinical features in the group of aniridia patients associated with aniridia were nystagmus, cataracts and glaucoma. PAX6 pathogenic mutations were identified in five out of six families (a diagnostic yield of 84%). Previously reported pathogenic mutations in PAX6 were identified in four families, which comprise p.R203*, p.R240* and p.R317*. In addition, a novel pathogenic variant (p.E220Gfs*23) was identified in a single family. No pathogenic mutations were detected in PAX6, FOXC1 or PITX2 in the only patient with a sporadic form of aniridia?like phenotype, confirming the genetic heterogeneity associated with this disease. To the best of our knowledge this is the first report on the mutational spectrum of PAX6 in aniridia patients of Cypriot ancestry. Mutational screening of PAX6 serves a crucial role in distinguishing isolated from syndromic forms of aniridia, and it may therefore eliminate the need for renal ultrasound scan surveillance, delineate the phenotype and improve genetic counseling.
| S-EPMC6072148 | biostudies-literature
Project description:To report a novel de novo PAX6 mutation in an Ashkenazi-Jewish family with autosomal dominant aniridia.A mother and her daughter of Ashkenazi-Jewish origin were diagnosed with aniridia. Blood samples were drawn from family members and DNA was analyzed by direct sequencing and microsatellite marker analysis.The index patient and her daughter were affected with aniridia accompanied by congenital cataract, nystagmus, and glaucoma. A heterozygous PAX6 frameshift mutation in exon 6 (c.577_578insG, insG@Gly72) was identified in the affected individuals and not in any of the unaffected family members including the parents of the index patient. Microsatellite analysis revealed that the index patient inherited the disease haplotype from her unaffected father. A sequence analysis of human PAX6 expressed sequence tags revealed the identification of spliced transcripts initiating from introns 4, 6, 7, 8, and 11.A novel de novo frameshift mutation in PAX6, which presumably occurred in the paternal gamete, was found in a family with autosomal dominant aniridia. The location of the mutation suggests that only full-length PAX6 isoforms would be disrupted, indicating that the normal expression of shorter, paired-less, protein isoforms cannot prevent manifestation of the disease.
| S-EPMC2255027 | biostudies-literature
Project description:To identify the disease-causing gene in a four-generation Chinese family affected with autosomal dominant aniridia and cataract.All patients underwent full ophthalmic examination. For mutation analysis, a partial coding region (exons 5-14) of paired box gene 6 (PAX6) was sequenced with DNA from the proband. Single-strand conformation polymorphism analysis for exon 5 of PAX6 was performed to demonstrate co-segregation of the PAX6 mutation with aniridia in all family members and the absence of the mutation in the normal controls.The proband and other patients in the family were affected with aniridia accompanied with congenital cataract. A novel heterozygous PAX6 mutation in exon 5 (c.475_491del17, p.Arg38ProfsX12) was identified, which was predicted to generate a frameshift and create a premature termination codon. This mutation co-segregated with the affected individuals in the family and did not exist in unaffected family members and 100 unrelated normal controls.A novel deletion mutation in the PAX6 gene was identified in a Chinese family with aniridia and congenital cataract. Our study expands the mutation spectrum of PAX6.
| S-EPMC2901194 | biostudies-literature
Project description:Purpose:The aim of this study was to detect the genetic defects in a large pedigree of affected individuals with various phenotypes of ocular anomalies including partial aniridia, congenital cataract, and nystagmus. Methods:The entire coding region of paired box gene 6 (PAX6) was amplified by polymerase chain reaction (PCR), sequenced, and compared with a GenBank database. Results:A novel mutation (c.1170 C > T; p.Gln297X) was found in the proband and all affected members. This nonsense mutation leads to PAX6 protein truncation. Conclusions:Our findings suggest that this novel mutation is most likely responsible for the pathogenesis of the congenital aniridia, cataract, and nystagmus in this pedigree. To the best of our knowledge, this is the first report of this mutation of PAX6 gene in a kindred pedigree with various ocular abnormalities.
| S-EPMC6127359 | biostudies-literature
Project description:Autosomal-dominant idiopathic infantile nystagmus has been linked to 6p12 (OMIM 164100), 7p11.2 (OMIM 608345) and 13q31-q33 (OMIM 193003). PAX6 (11p13, OMIM 607108) mutations can also cause autosomal-dominant nystagmus, typically in association with aniridia or iris hypoplasia. We studied a large multigenerational white British family with autosomal-dominant nystagmus, normal irides and presenile cataracts. An SNP-based genome-wide analysis revealed a linkage to a 13.4-MB region on chromosome 11p13 with a maximum lod score of 2.93. A mutation analysis of the entire coding region and splice junctions of the PAX6 gene revealed a novel heterozygous missense mutation (c.227C>G) that segregated with the phenotype and is predicted to result in the amino-acid substitution of proline by arginine at codon 76 p.(P76R). The amino-acid variation p.(P76R) within the paired box domain is likely to destabilise the protein due to steric hindrance as a result of the introduction of a polar and larger amino acid. Eye movement recordings showed a significant intrafamilial variability of horizontal, vertical and torsional nystagmus. High-resolution in vivo imaging of the retina using optical coherence tomography (OCT) revealed features of foveal hypoplasia, including rudimentary foveal pit, incursion of inner retinal layers, short photoreceptor outer segments and optic nerve hypoplasia. Thus, this study presents a family that segregates a PAX6 mutation with nystagmus and foveal hypoplasia in the absence of iris abnormalities. Moreover, it is the first study showing detailed characteristics using eye movement recordings of autosomal-dominant nystagmus in a multigenerational family with a novel PAX6 mutation.
| S-EPMC3925285 | biostudies-literature
Project description:To identify novel mutation in the PAX6 (paired box gene 6) gene and characterize new clinical features of severe ocular malformation in a Chinese patient with Peters' anomaly.A 10-month-old male infant, who presented with corneal opacity and nystagmus, was referred to our pediatric clinic and underwent a complete general physical and ophthalmological examination, including anterior segment and retinal evaluation with slit-lamp microscopy, an A/B ultrasonic scan, and electroretinography (ERG). Genomic DNA was prepared from venous leukocytes. The coding regions and the adjacent intronic sequence of PAX6 were amplified by a polymerase chain reaction, and subsequently analyzed by direct sequencing. The variation detected was further evaluated in 100 controls using heteroduplex- single strand conformational polymorphism (SSCP) analysis.The patient had bilateral Peters' anomaly showing congenital nystagmus, corneal leukoma with anterior synechia, anterior polar cataract, and his pupils could not be dilated because of posterior synechia. Electroretinography (ERG) demonstrated retina hypogenesis and an A/B ultrasonic scan showed microphthalmus. A novel mutation: C.51C>A (P. N17K) was identified in PAX6 while this mutation was absent in 100 normal controls. This mutation, which affects highly conserved amino acid, has not been previously reported.PAX6 mutations cause ocular malformations that vary considerably in pattern and severity. In this study, we identified one novel mutation in PAX6 in a patient with severe ocular clinical features of Peters' anomaly. This finding expands the mutation spectrum in PAX6 and enriches our knowledge of genotype-phenotype relations due to PAX6 mutations.
| S-EPMC2855731 | biostudies-literature
Project description:Forward genetics in the mouse continues to be a useful and unbiased approach to identifying new genes and alleles with previously unappreciated roles in mammalian development and disease. Here, we report a new mouse allele of Cse1l that was recovered from an ENU mutagenesis screen. Embryos homozygous for the anteater allele of Cse1l display a number of variable phenotypes, with craniofacial and ocular malformations being the most obvious. We provide evidence that Cse1l is the causal gene through complementation with a novel null allele of Cse1l generated by CRISPR-Cas9 editing. While the variability in the anteater phenotype was high enough to preclude a detailed molecular analysis, we demonstrate a very penetrant reduction in Pax6 levels in the developing eye along with significant ocular developmental phenotypes. The eye gene discovery tool iSyTE shows Cse1l to be significantly expressed in the lens from early eye development stages in embryos through adulthood. Cse1l has not previously been shown to be required for organogenesis as homozygosity for a null allele results in very early lethality. Future detailed studies of Cse1l function in craniofacial and neural development will be best served with a conditional allele to circumvent the variable phenotypes we report here. We suggest that human next-generation (whole genome or exome) sequencing studies yielding variants of unknown significance in CSE1L could consider these findings as part of variant analysis.
| S-EPMC8293161 | biostudies-literature
Project description:To identify mutations in the paired box 6 (PAX6) gene of 33 probands with aniridia and to reveal the mutational spectrum in the Chinese population.Unrelated probands with aniridia from 27 newly selected families and six previously analyzed families participated in this study. The coding regions of PAX6 in the 27 new families were analyzed using cycle sequencing. Families that lacked detectable variations based on sequencing (14 new and six previously analyzed) were further analyzed using multiplex ligation-dependent probe amplification (MLPA).Fifteen mutations were identified in 16 of the 33 families: c.[65_94del30; 99_105dup7], c.101_102insA, c.177delG, c.238_239insGCGA, c.1033-42_1033-26del17insG, c.1A>G, c.120C>A, c.718C>T, c.949C>T, c.1062C>A, c.1183G>A, c.1268A>T, and three gross deletions involving exons 1-14, exons 8-14, and exons 9-14. The first five mutations were novel and the c.1268A>T mutation was present in two families. Phenotypic variations were observed between families and between different affected patients within the families.The PAX6 mutation spectrum in Chinese aniridia patients is comparable to that reported in other ethnic groups. Further studies of the 17 families with no detected mutations may provide additional information to improve the understanding of the molecular genetics of aniridia.
| S-EPMC3156780 | biostudies-literature
Project description:Autosomal dominant keratitis (ADK) is an eye disorder chiefly characterized by corneal opacification and vascularization and by foveal hypoplasia. Aniridia (shown recently to result from mutations in the PAX6 gene) has overlapping clinical findings and a similar pattern of inheritance with ADK. On the basis of these similarities, we used a candidate-gene approach to investigate whether mutations in the PAX6 gene also result in ADK. Significant linkage was found between two polymorphic loci in the PAX6 region and ADK in a family with 15 affected members in four generations (peak LOD score = 4.45; theta = .00 with D11S914), consistent with PAX6 mutations being responsible for ADK. SSCP analysis and direct sequencing revealed a mutation in the PAX6 exon 11 splice-acceptor site. The predicted consequent incorrect splicing results in truncation of the PAX6 proline-serine-threonine activation domain. The SeyNeu mouse results from a mutation in the Pax-6 exon 10 splice-donor site that produces a PAX6 protein truncated from the same point as occurs in our family with ADK. Therefore, the SeyNeu mouse is an excellent animal model of ADK. The finding that mutations in PAX6 underlie ADK, along with a recent report that mutations in PAX6 also underlie Peters anomaly, implicates PAX6 broadly in human anterior segment malformations.
| S-EPMC1801269 | biostudies-other