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At least 199 records · Page 11Linked to original sources
PubMed2006

Nager acrofacial dysostosis: an unusual association with both upper and lower eyelid colobomas.

Nager acrofacial dysostosis comprises defects of cranio facial region and limbs (mostly upper) with variable associated anomalies. The cranio- facial complex is indistinguishable from the mandibulo facial dysostosis (Treacher Collins syndrome). About 80 cases have been described in the literature. We describe the case of a one-day-old male neonate who presented with the typical features of the disease complex. Although normal life span has been reported, our patient died on the second day due to cardio respiratory failure. We report this case because of its rarity and an unusual associated feature of bilaterally symmetrical upper and lower eyelid colobomas.

Abnormalities, Multiple↗
PubMed2006

Modified flexible iris retractor to retract superior iris and support inferior capsule in eyes with iris coloboma and inferior zonular deficiency.

Flexible nylon iris retractors are a useful adjunct to cataract surgery in cases of small pupil and subluxated lenses. A modification is presented of the standard application of iris hooks to retract the superior iris and support the inferior capsule during phacoemulsification in cases of iris coloboma with inferior zonular deficiency. Three iris hooks are applied to retract the iris, and 2 iris hooks are applied to the inferior capsule margin to support the crystalline lens in that quadrant. Clear corneal temporal phacoemulsification is then performed with adequate pupillary diameter and capsular support.

Coloboma↗
PubMed1995

Ophthalmoscopic visualization of the inferior ophthalmic vein through a chorioretinal coloboma.

PURPOSE/METHODS: In a patient with a coloboma of the optic nerve, inferior retina and choroid, and deep portions of the sclera, a retrobulbar vessel moved irregularly relative to the retinal vessels, which moved contiguously with the posterior globe. RESULTS/CONCLUSION: Fluorescein angiography showed the retrobulbar vessel filling slightly later than overlying retinal vessels. We conclude that the retrobulbar vessel was a vein situated inferiorly to the optic nerve.

Adult↗
PubMed1983

Hamartomatous adenoma of the nonpigmented ciliary epithelium arising in iris-ciliary body coloboma. Light and electron microscopic observations.

A 2 1/2-year-old boy had a slowly enlarging mass at the site of a typical iris-ciliary body coloboma for 2 years. The mass was excised partially by iridocyclectomy. By light microscopy, the tumor cells were embedded in a rich mucoid stroma that contained abundant hyaluronidase-sensitive acid mucopolysaccharides. By electron microscopy the tumor showed light and dark cells with interdigitating cell membranes, desmosomes, gap junctions, multilaminar basement membrane, and numerous extracellular collagen fibrils that resembled vitreous fibrils. We believe that the tumor represents a hamartomatous (congenital) adenoma of the nonpigmented ciliary epithelium rather than a conventional (acquired) adenoma, since it developed precisely within a colobomatous defect of the iris and ciliary body.

Adenoma↗
PubMed1998

Retinoblastoma in an eye with congenital uveal coloboma.

Retinoblastoma and congenital ocular abnormalities rarely coexist. The appearance of an intraocular tumor in a child with preexisting leukokoria may make the diagnosis of retinoblastoma more challenging. This report describes a unique case of unilateral congenital uveal coloboma and ipsilateral retinoblastoma in a patient with no family history of either abnormality and normal cytogenetic analysis.

Blotting, Southern↗
PubMed1995

Mutation of the PAX2 gene in a family with optic nerve colobomas, renal anomalies and vesicoureteral reflux.

Paired box (PAX) genes play a critical role in human development and disease. The PAX2 gene is expressed in primitive cells of the kidney, ureter, eye, ear and central nervous system. We have conducted a mutational analysis of PAX2 in a family with optic nerve colobomas, renal hypoplasia, mild proteinuria and vesicoureteral reflux. We report a single nucleotide deletion in exon five, causing a frame-shift of the PAX2 coding region in the octapeptide domain. The phenotype resulting from the PAX2 mutation in this family was very similar to abnormalities that have been reported in Krd mutant mice. These data suggest that PAX2 is required for normal kidney and eye development.

Abnormalities, Multiple↗
PubMed2000

PAX2 mutations in renal-coloboma syndrome: mutational hotspot and germline mosaicism.

The renal-coloboma syndrome (RCS, MIM 120330) is an autosomal dominant disorder caused by PAX2 gene mutations. We screened the entire coding sequence of the PAX2 gene for mutations in nine patients with RCS. We found five heterozygous PAX2 gene mutations: a dinucleotide insertion (2G) at position 619 in one sporadic RCS case, a single nucleotide insertion (619 + G) in three unrelated cases, and a single nucleotide deletion in a familial case. In this familial case, three affected sibs showed a striking ocular phenotypic variability. Each of the sibs carried a 619insG mutation, whilst unaffected parents did not, suggesting the presence of germline mosaicism. Interestingly, the 619insG mutation has been previously reported in several patients and is also responsible for the Pax21Neu mouse mutant, an animal model of human RCS. This study confirms the critical role of the PAX2 gene in human renal and ocular development. In addition, it emphasises the high variability of ocular defects associated with PAX2 mutations ranging from subtle optic disc anomalies to microphthalmia. Finally, the presence of PAX2 germline mosaicism highlights the difficulties associated with genetic counselling for PAX2 mutations.

Base Sequence↗
PubMed2003

Reciprocal fusion transcripts of two novel Zn-finger genes in a female with absence of the corpus callosum, ocular colobomas and a balanced translocation between chromosomes 2p24 and 9q32.

We have identified a female patient with a complex phenotype that includes complete agenesis of the corpus callosum, bilateral periventricular nodular heterotopia, and bilateral chorioretinal and iris colobomas. Karyotype analysis revealed an apparently balanced, reciprocal, de novo chromosome translocation t(2;9)(p24;q32). Physical mapping of the translocation breakpoint by fluorescence in situ hybridization and PCR analysis led to the identification of two novel, ubiquitously expressed, Zn-finger-encoding transcripts that are disrupted in this patient. Unexpectedly, the rearrangement produced in-frame reciprocal fusion transcripts, making genotype-phenotype correlation difficult.

Agenesis of Corpus Callosum↗
PubMed2001

A modification of the Mustardé technique for the surgical repair of a large feline eyelid coloboma.

A one-year-old male domestic short haired cat was referred because of an area of keratitis that had developed adjacent to a particularly large unilateral eyelid coloboma. The defect was repaired using an undescribed three-stage surgical technique, which is essentially a combination of existing techniques and consists of using the lower lid to re-construct the upper lid and replacing the resultant lower lid defect with a full thickness graft from the upper lip. This technique is described and the results illustrated by photographs. A good functional and cosmetic result was achieved.

Animals↗
PubMed1997

Coloboma hyperactive mutant mice exhibit regional and transmitter-specific deficits in neurotransmission.

The mouse mutant coloboma (Cm/+), which exhibits profound spontaneous hyperactivity and bears a deletion mutation on chromosome 2, including the gene encoding synaptosomal protein SNAP-25, has been proposed to model aspects of attention-deficit hyperactivity disorder. Increasing evidence suggests a crucial role for SNAP-25 in the release of both classical neurotransmitters and neuropeptides. In the present study, we compared the release of specific neurotransmitters in vitro from synaptosomes and slices of selected brain regions from Cm/+ mice with that of +/+ mice. The release of dopamine (DA) and serotonin (5-HT) from striatum, and of arginine vasopressin and corticotropin-releasing factor from hypothalamus and amygdala is calcium-dependent. Glutamate release from and content in cortical synaptosomes of Cm/+ mice are greatly reduced, which might contribute to the learning deficits in these mutants. In dorsal striatum of Cm/+ mutants, but not ventral striatum, KCl-induced release of DA is completely blocked and that of 5-HT is significantly attenuated, suggesting that striatal DA and 5-HT deficiencies may be involved in hyperactivity. Further, although acetylcholine failed to induce hypothalamic corticotropin-releasing factor release from Cm/+ slices, restraint stress increased plasma corticosterone levels in Cm/+ mice to a significantly higher level than in +/+ mice, suggesting an important role for arginine vasopressin in hypothalamic-pituitary-adrenal axis activation. These results suggest that reduced SNAP-25 expression may contribute to a region-specific and neurotransmitter-specific deficiency in neurotransmitter release.

Acetylcholine↗
PubMed2002

Cerebellar vermis defect, oligophrenia, congenital ataxia, and hepatic fibrocirrhosis without coloboma and renal abnormalities: report of three cases.

We describe 3 children (2 siblings aged 10 and 3 years, and 1 sporadic case aged 13 years) with cerebellar vermis defect associated with oligophrenia, congenital ataxia, and hepatic fibrocirrhosis. Differently from what is reported in COACH syndrome, coloboma and renal involvement were absent. Since in one patient hepatic involvement was subclinical and early therapy seemed to prevent disease progression, the presence of liver disease should be carefully investigated in any patient with ataxia and midline cerebellar defects.

Adolescent↗
PubMed1996

The mouse Pax2(1Neu) mutation is identical to a human PAX2 mutation in a family with renal-coloboma syndrome and results in developmental defects of the brain, ear, eye, and kidney.

We describe a new mouse frameshift mutation (Pax2(1Neu)) with a 1-bp insertion in the Pax2 gene. This mutation is identical to a previously described mutation in a human family with renal-coloboma syndrome [Sanyanusin, P., McNoe, L. A., Sullivan, M. J., Weaver, R. G. & Eccles, M. R. (1995) Hum. Mol. Genet. 4, 2183-2184]. Heterozygous mutant mice exhibit defects in the kidney, the optic nerve, and retinal layer of the eye, and in homozygous mutant embryos, development of the optic nerve, metanephric kidney, and ventral regions of the inner ear is severely affected. In addition, we observe a deletion of the cerebellum and the posterior mesencephalon in homozygous mutant embryos demonstrating that, in contrast to mutations in Pax5, which is also expressed early in the mid-hindbrain region, loss of Pax2 gene function alone results in the early loss of the mid-hindbrain region. The mid-hindbrain phenotype is similar to Wnt1 and En1 mutant phenotypes, suggesting the conservation of gene regulatory networks between vertebrates and Drosophila.

Abnormalities, Multiple↗
PubMed2004

Autosomal dominant brachydactyly, coloboma and anterior segment dysgenesis.

A three-generation family presenting with ocular developmental abnormalities, including anterior segment dysgenesis and coloboma, associated with brachydactyly and clinodactyly is presented. Several conditions incorporating ocular and bony limb abnormalities have been described. However, we believe that this family manifests a previously undescribed syndrome due to autosomal dominant or possibly x-linked inheritance with variable expression.

Adult↗
PubMed2002

Domain disruption and mutation of the bZIP transcription factor, MAF, associated with cataract, ocular anterior segment dysgenesis and coloboma.

Human congenital cataract and ocular anterior segment dysgenesis both demonstrate extensive genetic and phenotypic heterogeneity. We identified a family where ocular developmental abnormalities (cataract, anterior segment dysgenesis and microphthalmia) co-segregated with a translocation, t(5;16)(p15.3;q23.2), in both balanced and unbalanced forms. We hypothesized that this altered the expression of a gene of developmental significance in the human lens and ocular anterior segment. Cloning the 16q23.2 breakpoint demonstrated that it transected the genomic-control domain of MAF, a basic region leucine zipper (bZIP) transcription factor, first identified as an oncogene, which is expressed in vertebrate lens development and regulates the expression of the eye lens crystallins. The homozygous null mutant Maf mouse embryo demonstrates defective lens formation and microphthalmia. Through mutation screening of a panel of patients with hereditary congenital cataract we identified a mutation in MAF in a three-generation family with cataract, microcornea and iris coloboma. The mutation results in the substitution of an evolutionarily highly conserved arginine with a proline at residue 288 (R288P) in the basic region of the DNA-binding domain of MAF. Our findings further implicate MAF/Maf in mammalian lens development and highlight the role of the lens in anterior segment development. The 16q23.2 breakpoint transects the common fragile site, FRA16D, providing a molecular demonstration of a germline break in a common fragile site.

Amino Acid Sequence↗
PubMed1984

Congenital optic nerve colobomas: CT demonstration.

Patients with ocular coloboma and its variants may exhibit notching of the iris, peripapillary staphylomas, crater-like excavation of the optic disc, funnel-shaped widening of the retrobulbar optic nerve, cup-shaped filling defects in the perioptic subarchnoid space, and concurrent anomalies of the face, skull, and brain. Combined ophthalmological and radiological evaluation identifies these lesions successfully and differentiates them from other ocular pathology.

Abnormalities, Multiple↗