Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Coloboma”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10Linked to original sources
PubMed1982

Diagnostic precision in microphthalmos and coloboma of heterogeneous origin.

Heterogeneity of microphthalmos and coloboma is considerable and the clinical morphology is insufficient for etiological classification. A nosological classification has been performed in 86 cases of microphthalmos and coloboma occurring in mentally retarded individuals. Although nearly all were sporadic cases, a precise diagnosis could be established in 45 per cent of the cases. In 13 per cent, the phenotypes could not be assigned to any similar malformation syndrome described in the literature, and in 42 per cent the precision of the classification was low although the malformations had been repeatedly described before. An unknown number of the last-mentioned cases may have been environmentally induced, but little is known of environmentally induced ocular malformations and how to diagnose them after the first year of life.

Abnormalities, Multiple↗
PubMed1995

Autosomal dominant typical coloboma associated with unilateral pseudoptosis, myopia and cataract.

Ocular coloboma is considered to be hereditary ocular malformation which can manifest itself in various conditions ranging from iris defect to rudimentary cystic eye globe. We describe a three generation family affected by autosomal dominant typical coloboma, unilateral pseudoptosis, myopia and cataract. Correction of refractive errors improved their visual performance and prevented amblyopia. Genetic consultation was given in order to prevent blindness. We recommend a multidisciplinary approach regarding management of colobomatous patients.

Adult↗
PubMed1993

Optic disc coloboma associated with macular hole and retinal detachment.

A 15-year-old myopic girl had a retinal detachment associated with optic disc coloboma and a macular hole. The retinal detachment was treated successfully with vitrectomy, drainage of the subretinal fluid, and gas tamponade. The possibility of a macular hole should be investigated in myopic eyes with optic disc colobomas and retinal detachments. To the best of our knowledge, such a combination has not been described previously.

Adolescent↗
PubMed1996

Systemic abnormalities associated with iris/nerve head/choroidal/retinal coloboma.

A case is reported in which large colobomas of the retina and choroid are found bilaterally in a young female who also has a pituitary tumor and mental retardation. Visual field data are presented and correlated with the retinal appearances. Relevant embryology is reviewed, and a table of systemic abnormalities associated with retinal/choroidal colobomas is presented.

Adenoma↗
PubMed2001

Neuromuscular transmission and muscle contractility in SNAP-25-deficient coloboma mice.

Synaptosomal associated protein of 25 kDa (SNAP-25) is a cytoplasmic protein that participates in the docking and fusion of synaptic vesicles with the nerve terminal in preparation for neurotransmitter release. SNAP-25 is also a substrate for three of the seven serotypes of botulinum neurotoxin (BoNT). Intoxication by BoNT/A, /C1 or /E results in weakness and paralysis of skeletal muscle due to cleavage of SNAP-25 (and syntaxin la in the case /C1) at discrete serotype-specific sites. To elucidate the role of SNAP-25 in muscle function in more detail, contractility and neuromuscular transmission were studied in a mutant mouse model termed coloboma. The coloboma mutation results from a contiguous deletion of 1-2 centiMorgans on chromosome 2, which includes the entire SNAP-25 locus and three other identified genes. Homozygotes do not survive beyond gestation day 6; heterozygotes (Cm/+) have a normal life-span but express reduced levels of SNAP-25 mRNA and protein in the brain. The consequences of the Cm/+ mutation on twitch and tetanic tension, quantal release of neurotransmitter and spinal motoneuron expression of SNAP-25 were examined in the present study. Contrary to expectations, Cm/+ mice exhibited no alteration in twitch tension and generated normal tetanic tension even at the highest frequency examined (800 Hz). Microelectrode recordings revealed that MEPP amplitude and frequency were both within control limits. The ventral spinal cord of Cm/+ mice showed no deficiency in SNAP-25 content and immunohistochemical examination of nerve terminals in Cm/+ mice disclosed that SNAP-25 levels and distribution were similar to those of control mice. It is concluded that spinal motor neurons up-regulate SNAP-25 to preserve vital neuromuscular function.

Aminopyridines↗
PubMed2001

Differentiation and migration of astrocyte precursor cells and astrocytes in human fetal retina: relevance to optic nerve coloboma.

The presence of astrocyte precursor cells (APCs) and time course and topography of astrocyte differentiation during development were investigated by triple-label immunohistochemistry with intact fetal and adult human retinas. Throughout retinal development and adulthood, expression of Pax2 was restricted to cells of the astrocytic lineage. Three distinct stages of astrocytic differentiation were identified during development: i) Pax2+/vimentin+/GFAP- APCs; ii) Pax2+/vimentin+/GFAP+ immature perinatal astrocytes; and iii) Pax2+/vimentin-/GFAP+ mature perinatal astrocytes. In adult, cells with the antigenic phenotype of mature perinatal astrocytes were restricted to a region surrounding the optic nerve head (ONH), whereas cells at a fourth stage of differentiation, adult astrocytes (Pax2-/vimentin-/GFAP+), were apparent throughout the vascularized retina. APC appearance was centered around the ONH and preceded the appearance of perinatal astrocytes. A cluster of Pax2+ somas was also present in a small region surrounding the ONH at the ventricular surface of the developing retina, which suggests the existence of two distinct sites of astrocytic differentiation. The coincidence in the location of APCs and perinatal astrocytes at the ventricular zone with that of optic nerve colobomas, together with the association of Pax2 gene mutations with this condition, suggests that coloboma formation may result from impaired astrocyte differentiation during development.

Adult↗
PubMed2000

Influence of selective breeding on the prevalence of chorioretinal dysplasia and coloboma in the rough collie in Sweden.

A total of 8204 rough collies, representing 76 per cent of all collies registered by the Swedish Kennel Club between 1989 and 1997, were examined before 10 weeks of age for collie eye anomaly (CEA). All dogs were permanently identified and examination results were registered and computerised. The policy of breeders during the study period was to select against coloboma in breeding stock, but to allow breeding of chorioretinal dysplasia (CRD) affected animals. The prevalence of CRD increased significantly from 54.2 per cent to 68.1 per cent (P < 0.001) from 1989 to 1997, while the prevalence of coloboma did not (8.3 per cent to 8.5 per cent, P = 0.4). These results are not compatible with a simple, recessive, autosomal inheritance for the entire CEA complex.

Animal Husbandry↗
PubMed2002

[Macular coloboma type Leber's congenital amaurosis].

Three brothers, with the macular coloboma type Leber's congenital amaurosis aged 10, 8, and 6 years respectively, are described in this report. Only the two elder brothers were symptomatic while the third patient had no complaint at the time of diagnosis. The patients had no associated systemic or ocular disorders, including nystagmus. They had mild myopic astigmatism. All three had a relatively well-circumscribed bilateral macular atrophy with a seemingly normal peripheral retina. The electroretinogram was non recordable but the visualy evoked potential responses were within normal limits. During three years of follow-up, the macular lesions did not progress and the visual acuity did not deteriorate further. Our experience with these three familial cases supports the general view that the macular coloboma variant does not necessarily have the typical signs and symptoms and perhaps also the dismal prognosis of classic Leber's congenital amaurosis, and as such should stand as a distinct subtype of the disease.

Blindness↗
PubMed2004

Pathogenic implications of subretinal gas migration through pits and atypical colobomas of the optic nerve.

OBJECTIVE: To describe subretinal migration of gas and silicone oil in a series of patients with congenital cavitary optic disc anomalies and to further clarify the pathogenesis of the associated maculopathy. METHODS: Medical records of 4 female patients, aged 8 to 34 years, who developed subretinal gas migration after vitreous surgery for macular detachment associated with cavitary optic disc anomalies were reviewed. A theoretical model was used to calculate the pressure differential required to induce subretinal gas migration through an optic pit. RESULTS: The 4 patients had bilateral atypical optic nerve colobomas or a unilateral large optic pit. A definite defect in the tissue overlying the disc excavation could be seen in one eye, and intraoperative drainage of subretinal fluid through the disc anomaly was possible in all cases. Subretinal migration of gas or silicone oil was seen intraoperatively in one case and first appeared between 1 and 17 days postoperatively in the remaining cases. Theoretical calculations suggest that the pressure differential required for migration of gas through a small defect in the roof of a cavitary disc lesion is within the range of expected fluctuations in cerebrospinal fluid pressure. CONCLUSIONS: These observations provide clinical confirmation of a defect in tissue overlying cavitary optic disc anomalies and imply interconnections between the vitreous cavity, subarachnoid space, and subretinal space. We theorize that intermittent pressure gradients resulting from normal variations in intracranial pressure play a critical role in the pathogenesis of retinopathy associated with cavitary disc anomalies.

Adult↗
PubMed1996

Treacher Collins syndrome: phenotypic variability in a family including an infant with arhinia and uveal colobomas.

We report extreme expression of Treacher Collins syndrome in an infant with arhinia, anotia, absent zygomatic bones, hypoplastic mandibular rami, and bilateral coloboma of iris, choroid plexus, and optic nerves. The Treacher Collins phenotype was mildly expressed in the mother and moderately in the sister. The father had no signs and was not ruled out as the father by DNA fingerprinting, thus making homozygosity by descent in the severely affected son very unlikely.

Adult↗
PubMed2002

New mental retardation syndrome associated with ocular colobomas, cleft palate, and genital, skeletal, and craniofacial abnormalities.

We describe three Canadian brothers of Cree origin, with a previously undescribed pattern of malformation including distinctive craniofacial abnormalities with triangular facies, hypertelorism, low-set and posteriorly rotated ears, ocular colobomas, ptosis, brachycephaly with widely separated sutures, cleft soft palate, undescended testes, bifid scrotum and hypospadius, wide webbed neck, webbed fingers, pectus excavatum and hypersegmented sternum, and severe psychomotor retardation. The presence of normal brain imaging and physical growth distinguishes them from other syndromes with overlapping abnormalities. This is either an X-linked or autosomal recessive condition.

Abnormalities, Multiple↗
PubMed1980

Congenital macular colobomas and short-limb skeletal dysplasia.

We report a previously undescribed association of severe short-limbed dwarfism and macular colobomas with histological changes of cartilage resembling to some extent those of diastrophic dysplasia. Chance occurrence of two rare disorders due to different causes is considered unlikely and the patient is presumed to have a syndrome of, as yet, unknown cause.

Bone and Bones↗
PubMed2003

A new X-linked syndrome with agenesis of the corpus callosum, mental retardation, coloboma, micrognathia, and a mutation in the Alpha 4 gene at Xq13.

We describe two brothers with a unique pattern of malformations that includes coloboma (iris, optic nerve), high forehead, severe retrognathia, mental retardation, and agenesis of the corpus callosum (ACC). Both boys have low-set cupped ears with sensorineural hearing loss, normal phallus, pectus excavatum, scoliosis, and short stature. One brother had choanal atresia and cardiac defects consisting of ventricular septal defect (VSD) and patent ductus arteriosus (PDA) which resolved spontaneously. Differential diagnosis between a number of clinical entities was considered, however, because ACC and the distinctive facial features were reminiscent of FG syndrome, DNA was analyzed for markers linked to the FGS1 locus at Xq13-q21. Notably, the brothers were concordant for markers spanning this presumed FG region, and in both we have identified adjacent alterations (-57delT and T-55A) in the Alpha 4 gene located within this interval. Alpha 4 is a regulatory subunit of the major cellular phosphatase, PP2A, that has recently been shown to interact with MID1, the product of the gene mutated in X-linked Opitz GBBB syndrome. The double nucleotide change identified in this family was not observed in 410 control chromosomes, suggesting that it may be a pathogenetic change. Altered expression of Alpha 4, through either a change in translational efficiency, mRNA stability or splicing, could explain the clinical phenotype in these boys and the phenotypic overlap with Opitz GBBB syndrome.

Adaptor Proteins, Signal Transducing↗
PubMed2004

Ocular coloboma and high myopia with Hirschsprung disease associated with a novel ZFHX1B missense mutation and trisomy 21.

Syndromic Hirschsprung disease has been associated with mutations in ZFHX1B, a Smad-interacting transcriptional repressor protein. Tissue in situ hybridization has demonstrated strong expression of ZFHX1B in the developing eye, suggesting that some mutations in this gene may cause visual loss. However, none of the reported mutations have been associated with an ocular phenotype. We describe a patient with Down syndrome and Hirschsprung disease with high myopia and ocular coloboma affecting the iris and retina. In addition to trisomy 21, a novel, de novo heterozygous A to G transition in exon 8 of the ZFHX1B gene was identified, which results in a R953G amino acid substitution. This abnormality was not seen in a screen of 200 chromosomes from ethnically matched, normal controls. The arginine residue at position 953 is an extremely conserved amino acid throughout evolution. This is the first report associating Hirschsprung disease and severe eye defects with a specific genetic mutation and is the first report of a mutation in ZFHX1B causing a developmental ocular anomaly.

Abnormalities, Multiple↗
PubMed1994

Deletion map of the coloboma (Cm) locus on mouse chromosome 2.

The extent of the semidominant coloboma (Cm) mutation on mouse Chromosome 2 was determined by deletion mapping using interspecific hybrid mice. The Cm deletion mutation results in ophthalmic dysmorphology and behavioral deficits, including profound hyperactivity, and has been shown to encompass the gene Snap. In addition to Snap, the gene encoding phospholipase C beta-1 (Plcb-1), which maps 0.60 +/- 0.60 cM proximal to Snap, and simple sequence repeat (SSR) loci D2Mit19, D2Mit46, D2Mit28, and D2Mit136 were shown to be deleted at the Cm locus. In contrast, analysis of other closely linked SSRs and genes either proximal (Bmp-2a) or distal (Nec-1) to Snap, as well as a complementation test with the closely linked mutation lethal milk (lm), indicates that these gene sequences are unaffected by the Cm mutation. These data demonstrate that the Cm deletion represents a contiguous gene defect encompassing 1.1 to 2.2 cM that may be probed for genes, both in the mouse and in the syntenic region of human Chr 20, that independently affect elements of neurological behavior and eye development.

Animals↗
PubMed1983

A discussion of 61 cases of optic nerve coloboma.

Colobomata of the optic disc result from failure of closure of the most anterior portion of the optic stalk. Therefore the great majority of these defects are found at the six o'clock position in the region of the embryonic defect. The authors examined 61 patients with optic nerve coloboma from 1972 to 1983. The clinical data of these patients are given. It was remarkable that the optic nerve colobomata occurred in combination with the same systemic and 'midline'-defects that are often seen in combination with optic nerve hypoplasia.

Abnormalities, Multiple↗
PubMed1989

Bilateral macular colobomas in Leber's congenital amaurosis.

Two siblings with Leber's congenital amaurosis had bilateral macular colobomas, nystagmus, extinguished ERGs, and degenerative salt and pepper like changes in the fundus. They had non-recordable or non-meaningful visually evoked cortical potentials in response to both flash and pattern stimuli. The ophthalmic conditions were thought to be inherited as an autosomal recessive trait.

Adolescent↗