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At least 73 records · Page 4Linked to original sources
PubMed2005

A population-based case-control study of isolated ocular coloboma.

AIMS: To attempt the detection of possible etiological factors in the origin of isolated ocular, mainly iris coloboma. METHODS: The data set of the Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980-2002, was used. Exposure data and family history were based on (1) prospective medical records, (2) retrospective maternal information, and (3) information obtained by regional nurses at home visit. RESULTS: Of 46 cases, 40 were affected with iris coloboma and 19 had bilateral manifestation. The positive family history indicated a hereditary origin in 4.3% (2/46) of cases. An association was found between the isolated ocular coloboma and hydroxyethylrutoside treatment (adjusted POR with 95% CI: 5.4, 2.2-12.9). Another association was seen between isolated ocular coloboma and hypothyroidism (adjusted OR with 95% CI = 12.6, 3.0-52.7), but it was based only on two cases. CONCLUSIONS: It is necessary to study the preventable environmental factors in the origin of these ocular defects.

Abnormalities, Drug-Induced↗
PubMed2002

Congenital upper lid colobomas: management and visual outcome.

PURPOSE: Congenital upper lid colobomas may be associated with ocular and systemic anomalies. The ophthalmologist's role involves both the diagnosis and management of their various ocular structural defects and management of the visual development. METHODS: All cases of congenital eyelid colobomas referred to the Singapore National Eye Centre between July 1992 and July 1995 were assessed for the extent of the eyelid defect, associated ocular anomalies, status of the cornea, and any systemic anomalies. RESULTS: Four infants were tested during this period. The mean follow-up was 25 months (range, 16 to 30 months). All required surgical correction of their eyelid defects before 2 years of age. The patients also had refractive errors requiring amblyopia management. Three of the babies also needed other surgical procedures. CONCLUSIONS: Congenital upper eyelid colobomas are a potential threat to vision at an early age and a significant cosmetic blemish later in life. Early surgical intervention is usually required when the defect is larger than one third of the eyelid margin. Close monitoring of the visual development of patients with congenital upper eyelid colobomas is also essential since the risk of amblyopia in these patients is high.

Coloboma↗
PubMed2003

Ultrasound biomicroscopy in lens "coloboma".

PURPOSE: To study the morphology of the Lens "Coloboma" using the technique of ultrasound biomicroscopy. METHODS: We used the Paradigm 40 Ultrasound biomicroscope to study the morphology of the lens "Coloboma". RESULTS: Ultrasound biomicroscopy of the lens "Coloboma" revealed a greatly increased sphericity of the lens and the deficiency of zonules in the "colobomatous" area. CONCLUSIONS: Ultrasound biomicroscopy has helped in elucidating the pathology of the lens "Coloboma".

Coloboma↗
PubMed2003

Unilateral giant coloboma of the upper eyelid associated with other congenital anomalies (33 years follow-up of surgical repair).

PURPOSE: To describe a case of congenital unilateral giant coloboma and its successful surgical repair with 33 years of follow-up. CASE REPORT: A 6-year-old boy presented with a congenital unilateral giant coloboma of the right upper eyelid associated with madarosis of the eyebrows, microphthalmos, dystopia of the hair, and coloboma of the apex of the nose. The patient underwent surgical repair of the multiple anomalies in different steps. DISCUSSION: A multiple-step, two-layer technique for the reconstruction of the right upper eyelid was performed in a 6-year-old boy with congenital unilateral giant coloboma associated with multiple ocular and facial anomalies. After 33 years of follow-up, the cosmetic results are excellent, although it has not been possible to preserve the visual function of the right eye, which had to be enucleated.

Abnormalities, Multiple↗
PubMed2004

Colobomas of the iris in a flock of rosecomb bantam chickens.

A defect in the pupil shape ofrosecomb bantam chickens was noticed by a breeder. The pupil in affected birds appeared to be elongated at the lower margin and consistent with a coloboma of the iris. Upon examination of all birds in the flock, the defect was found in 26% of females and 9% of males. Examination of breeders older than 1 yr led to the discovery ofcolobomas, although there were not enough birds to accurately determine the prevalence of the problem for previous generations. Affected birds were examined for other lesions, and none were found. Specific-pathogen-free (SPF) eggs were incubated and hatched with eggs from the affected flock as sentinels. No SPF chicks developed colobomas of the iris, while 37% of the bantams in the same hatch were affected. This experiment eliminated many possible infectious agents and incubator or brooder malfunction as causes of this eye lesion. An analysis of the flock pedigree suggested that the defect might be inherited and might be related either to feather color or to gender. No statistically significant correlation could be made between feather color and the iris colobomas. However, the trait was twice as likely to occur in females as in males, which suggests that it is a sex-influenced trait. Based on the determination that this was an inherited trait, a breeding strategy to reduce the prevalence of the lesion in which affected birds were removed from the breeding flock was developed and followed for 2 yr. The prevalence of colobomas was 22% in females and 2.9% in males after the first year and 7.8% and 0.8% in females and males, respectively, after the second year.

Analysis of Variance↗
PubMedDate not supplied

Limb-body wall complex with anophthalmos and choroidal coloboma.

A 23-year-old primigravida underwent induced abortion in the 17th week of pregnancy because ultrasound fetometry had indicated possible encephalocele/hygroma of the skull and deformities of limbs and abdominal wall. The fetus delivered showed a deep facial cleft, absence of nose and maxilla, absence of parietal and frontal bones, missing right upper extremity, and a large thoracoabdominal defect with herniation of internal organs. The placenta was large, with an amniotic fold across the fetal surface. The brain was holoprosencephalic with a midline monoventricle and with focal brain wall dysplasia. The right orbit and eye were absent. The left eye was microphthalmic, with an abnormal cornea, a large choroidal coloboma inferiorly, a dysplastic retina, and a cataractous spherical lens. Theories discussed are pathogenesis of the limb-body wall complex (LBWC) and ocular malformations, particularly uveal coloboma. Previous cases of anophthalmos and uveal coloboma are listed. Microscopic examination of the eye was performed in only one of these. The present case is the sixth case published of choroidal coloboma in association with the LBWC.

Abnormalities, Multiple↗
PubMed2005

Structural organization of choroidal colobomas of young and adult patients and mechanism of retinal detachment.

PURPOSE: In colobomatous eyes, the risk of retinal detachment increases with age. This study elucidates the anatomic conditions and pathologic process of retinal detachment associated with colobomas. METHODS: The records, including histologic slides, of 14 children (1 day to 17 months old) and 7 adults (17 to 78 years old) with colobomas were examined. RESULTS: In children, colobomas were associated with lethal malformations. The extracolobomatous inner retinal layers extended centrally, forming the intercalary membrane. Duplication of the outer retinal layers and a horizontal shift of Müllerian glia created a triangle and a locus minoris resistentiae adjacent to the laterally displaced pigment epithelium. Part of the locus was an incomplete layer of photoreceptors excluding Müllerian glia. In adults, atrophy of the intercalary membrane, manifested as central schisis, thinning of the neuroepithelium, and hole formation, was related to a paucity of blood vessels within and underneath the intercalary membrane and the size of colobomas. The margins featured blood vessels, pigment epithelial hypertrophy, and choroidal and scleral thickening in a compact, intertwined arrangement. CONCLUSIONS: Glial atrophy, schisis, and hole formation in the intercalary membrane and separation of the locus minoris resistentiae from the pigment epithelium can disrupt barriers to fluid flow and set the stage for rhegmatogenous retinal detachment. That process is exacerbated by scleral ectasia, increasing vitreous traction at the margin, and retinovascular ischemia within the intercalary membrane. A vascularized, compact margin resembling a laser barrier, found predominantly in adults, may protect against retinal detachment.

Adolescent↗
PubMed1989

[Macular coloboma and alternating diffuse chorio-retinal dysplasia].

The author reports on two siblings. The elder, a 28-year-old woman has bilateral macular coloboma and a high degree of myopia. Her 27-year-old brother's left eye also has a macular coloboma, while his right eye has diffuse chorioretinal dysplasia with extensive nevoid choroidal pigmentation but no macular coloboma. His right eye is hyperopic, the left myopic. The eyes of the parents and their other, younger daughter are normal in all respects. Congenital syphilis and toxoplasmosis have been excluded as causes of the fundus deterioration of the first two offsprings. The macular colobomas of the two siblings (circumscribed macular dysplasia) and the alternating diffuse chorioretinal dysplasia must be classified as genetically conditioned maldevelopment of the optic cup ectoderm.

Adult↗
PubMed1993

Phenotypic correlations of ocular coloboma without known cause.

Ocular coloboma can occur as an autosomal dominant condition or as part of a known syndrome or chromosomal abnormality. We have designated those patients with ocular coloboma who do not fit into any of these three groups as having coloboma without known cause. We completed a retrospective review of 58 patients from our clinics with coloboma without known cause to determine the frequency of other co-existing congenital malformations and mental retardation. Mental retardation was present in 14 of the 42 patients (33%) who were more than 1 year of age. However, only 14% of the children who had no other malformations had mental retardation, whereas 57% of those with other malformations were mentally retarded. We found that the severity of the colobomatous malformation did not correlate with intellect.

Adolescent↗
PubMed1995

Absence of linkage of apparently single gene mediated ADHD with the human syntenic region of the mouse mutant Coloboma.

Attention deficit disorder (ADHD) is a complex biobehavioral phenotype which affects up to 8% of the general population and often impairs social, academic, and job performance. Its origins are heterogeneous, but a significant genetic component is suggested by family and twin studies. The murine strain, coloboma, displays a spontaneously hyperactive phenotype that is responsive to dextroamphetamine and has been proposed as a genetic model for ADHD. Coloboma is a semi-dominant mutation that is caused by a hemizygous deletion of the SNAP-25 and other genes on mouse chromosome 2q. To test the possibility that the human homolog of the mouse coloboma gene(s) could be responsible for ADHD, we have carried out linkage studies with polymorphic markers in the region syntenic to coloboma (20p11-p12). Five families in which the pattern of inheritance of ADHD appears to be autosomal dominant were studied. Segregation analysis of the traits studied suggested that the best fitting model was a sex-influenced, single gene, Mendelian pattern. Several genetic models were evaluated based on estimates of penetrance, phenocopy rate, and allele frequency derived from our patient population and those of other investigators. No significant linkage was detected between the disease locus and markers spanning this chromosome 20 interval.

Adolescent↗
PubMed2006

The alpha(2C)-adrenergic receptor mediates hyperactivity of coloboma mice, a model of attention deficit hyperactivity disorder.

Drugs that modify noradrenergic transmission such as atomoxetine and clonidine are increasingly prescribed for the treatment of attention deficit hyperactivity disorder (ADHD). However, the therapeutic targets of these compounds are unknown. Norepinephrine is also implicated in the hyperactivity exhibited by coloboma mice. To identify the receptor subtypes that regulate the hyperactivity, coloboma mice were systematically challenged with adrenergic drugs. The beta-adrenergic receptor antagonist propranolol and the alpha(1)-adrenergic receptor antagonist prazosin each had little effect on the hyperactivity. Conversely, the alpha(2)-adrenergic receptor antagonist yohimbine reduced the activity of coloboma mice but not control mice. Subtype-selective blockade of alpha(2C)-, but not alpha(2A)- or alpha(2B)-adrenergic receptors, ameliorated hyperactivity of coloboma mice without affecting activity of control mice, suggesting that alpha(2C)-adrenergic receptors mediate the hyperactivity. Localized in the basal ganglia, alpha(2C)-adrenergic receptors are in a prime position to impact locomotor activity and are, therefore, potential targets of pharmacotherapy for ADHD.

Adrenergic alpha-Antagonists↗
PubMed1980

Cavitary developmental defects of the optic disc. Visual loss associated with optic pits and colobomas.

Congenital cavitary anomalies of the optic disc (optic pit and coloboma) are uncommon and frequently go unrecognized. Patients with these defects have a high incidence of visual loss and the abnormal appearance of the discs may be mistaken for atrophy due to acquired neurological disease. Occasionally, associated midline neurological developmental malformations will be found associated with pits, colobomas, or other dysplastic optic discs, as in one of our cases. A group of patients with optic pits and colobomas referred for neurological evaluation of visual loss are presented to remind the neurologist of the appearance of these congenital crater-like defects and of the causes of loss of vision.

Adult↗
PubMed1991

Vitreous surgery for retinal detachment associated with choroidal coloboma.

We report the results of vitreous surgery in seven eyes with retinal detachments caused by retinal breaks at the margin of, or within, a choroidal coloboma. All seven eyes (100%) were reattached; visual acuities in five (71%) of the seven eyes improved from preoperative levels. Vitrectomy was combined with air-fluid exchange and endodrainage through preexisting retinal breaks or planned retinotomies in all but one of the cases. Part or all of the rim of the choroidal coloboma in six eyes underwent endophotocoagulation. The two eyes that did not experience postoperative visual improvement underwent intraoperative endolaser treatment 360 degrees around the optic nerve. If peripapillary endophotocoagulation is performed, especially through the papillomacular bundle, nerve fiber damage may occur and prevent visual recovery, despite retinal reattachment. For eyes with retinal detachment associated with choroidal colobomas involving the optic nerve, postoperative laser treatment through the papillomacular bundle may be preferable.

Adolescent↗
PubMed1988

Optic nerve coloboma associated with renal disease.

Optic nerve colobomas can occur as sporadic abnormalities, may be inherited as an autosomal dominant defect, occur as part of syndromes, and are rarely associated with cardiac malformations and midline encephaloceles. Karcher [1979] described a father and son with the "morning glory" optic disc anomaly and renal disease as a new association. We report on two brothers with optic nerve colobomas associated with renal disease. The ophthalmologic findings and renal histopathology are presented. This second familial occurrence suggests that the association of optic nerve coloboma and renal disease is a newly recognized syndrome.

Child↗
PubMed2003

Coloboma and other ophthalmologic anomalies in Kabuki syndrome: distinction from charge association.

Kabuki (Niikawa-Kuroki) syndrome is associated with growth retardation, developmental delay, congenital heart disease, cleft palate, and characteristic facial features. Although the external appearance of the eyes has been well-described, the type and frequency of structural and functional eye anomalies has not been emphasized. We report three children with Kabuki syndrome who also had a retinal coloboma. A diagnosis of CHARGE association was initially suggested in two of the patients before the typical facial features of Kabuki syndrome emerged. A detailed review of reported cases of Kabuki syndrome shows that a variety of eye anomalies are associated with Kabuki syndrome. The incidence of coloboma is greatly increased in Kabuki syndrome. Thus, ophthalmologic abnormalities are frequently associated with Kabuki syndrome, and an ophthalmologic evaluation should be performed for each patient. Phenotypic overlap, including congenital heart, ear, and renal defects, can lead to the diagnosis of CHARGE association, especially since the typical facial features of Kabuki syndrome may not be apparent in early infancy. Thus, Kabuki syndrome should be considered in patients with coloboma if other features consistent with this condition are present, and follow-up evaluations are indicated for establishing the proper diagnosis.

Abnormalities, Multiple↗
PubMed1981

Development of coloboma (Cm/+), a mutation with anterior lens adhesion.

A semidominant mutation in the laboratory mouse, Coloboma (Cm), is described. Coloboma is located on Chromosome 2, as is the similar mutation Dickie's small eye (Dey). Coloboma has a moderately reduced expressivity. The anterior chamber is usually present in Cm/+. Both Cm and Dey show delayed detachment of the lens vesicle and microphthalmia, and homozygotes of both apparently die early in pregnancy.

Animals↗
PubMed1989

Bilateral colobomas in a horse.

Bilateral true colobomas with retrobulbar cysts located over the optic nerves are described in an 8-year-old Quarterhorse mare with a history of progressive blindness. Colobomas result from the failure of an embryonic fissure to close and retrobulbar cysts result from eversion of the neuroectoderm through the colobomas. It could not be determined whether the small optic nerves and the scars, rosettes and disorganization of the cell layers in the retina were the result of concurrent dysplasia or were secondary to degeneration.

Animals↗
PubMed2001

Renal-coloboma syndrome: report of a novel PAX2 gene mutation.

PURPOSE: To report a novel sporadic PAX2 gene mutation in a child with atypical bilateral optic nerve coloboma and congenital renal hypoplasia. DESIGN: Observational case report and experimental study. METHODS: Mutational analysis of the PAX2 gene in a family. RESULTS: A 9-year-old patient with a history of renal transplantation for congenital renal hypoplasia was found to have bilateral optic nerve coloboma during ophthalmic examination for cytomegalovirus retinitis. A previously unreported mutation in exon 2, delT 602 leading to a prematurely truncated protein was identified in the child but in neither of her parents, demonstrating a de novo mutation or germline mosaicism. CONCLUSIONS: The causal relationship between PAX2 gene mutations and renal-coloboma syndrome is further supported by this novel mutation. Awareness of the systemic associations with optic nerve abnormalities and the ocular findings in syndromic renal diseases will facilitate the management of these highly variable disorders.

Abnormalities, Multiple↗