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PubMed2002

Split hand/split foot, iris/choroid coloboma, hypospadias and subfertility: a new developmental malformation syndrome?

This paper presents a patient with the following malformations: split hand and split foot on the left side, a hypoplastic fifth ray of the right hand and a hypoplastic first ray of the right foot with a small cleft between the first and second ray; eye abnormalities which consist of a complete iris coloboma of the left eye in an atypical position (cranio-temporal) and a coloboma of the choroid in the right eye; a glandular hypospadias and terato-zoospermia. Since split hand/split foot can be caused by mutations in the p63 gene, mutation analysis of this gene was performed. However, sequencing analysis did not reveal a mutation. This malformation complex may represent a new syndrome.

Abnormalities, Multiple↗
PubMed1995

Unexpected familial recurrence of iris coloboma. A delayed mutation mechanism?

Typical isolated ocular coloboma is a congenital abnormality caused by a defective closure of the embryonic fissure of the optic cup. Although an irregular autosomal dominant mechanism of inheritance has been proposed, there is some evidence of other modes of transmission and etiologies. This report shows an unexpected recurrence of iris coloboma, occurring in three sibships of the same family, that could be explained by a "delayed mutation" or "premutation" mechanism.

Child↗
PubMed1989

Morning glory syndrome associated with marked persistent hyperplastic primary vitreous and lens colobomas.

A case of morning glory syndrome with striking persistence of primary vitreous is presented. The hypothesis that the syndrome is an expression of abnormal closure of the embryonic fissure is substantiated by the coexistence of lens colobomas. Furthermore, the marked primary vitreous hyperplasia shows the way in which persistence of primary vitreous influences the clinical expression with respect to optic pit and colobomas of the optic nerve.

Adolescent↗
PubMed1992

Bilateral macular coloboma and pigmented paravenous retinochoroidal atrophy.

A patient had bilateral macular coloboma with aggregations of pigment clumps located perivascularly, predominantly paravenously, and in other parts of the retina. The Toxoplasma IgG antibody was negative. The diagnosis of bilateral macular coloboma with pigmented paravenous retinochoroidal atrophy was made and seemed to be a developmental abnormality in origin.

Adult↗
PubMed2003

The familial contribution to non-syndromic ocular coloboma in south India.

AIMS: To identify the proportion of familial cases of isolated ocular colobomatous malformations in a case series from south India. METHODS: Children with ocular coloboma without systemic features were recruited from multiple sources in Andhra Pradesh, India. Their families were traced, pedigrees drawn, and family members examined. RESULTS: 56 probands, 25 females (44.6%) and 31 males (57.4%) with a colobomatous malformation were identified. In 12 cases (21.4%) another family member was affected. The risk to siblings was 3.8%. The parents were consanguineous in 25 cases (44.6%). CONCLUSIONS: 21.4% of cases of isolated ocular coloboma in this highly consanguineous population of south India were familial, with both autosomal dominant and autosomal recessive mechanisms likely in different families.

Adolescent↗
PubMed2004

Ocular coloboma: a reassessment in the age of molecular neuroscience.

Congenital colobomata of the eye are important causes of childhood visual impairment and blindness. Ocular coloboma can be seen in isolation and in an impressive number of multisystem syndromes, where the eye phenotype is often seen in association with severe neurological or craniofacial anomalies or other systemic developmental defects. Several studies have shown that, in addition to inheritance, environmental influences may be causative factors. Through work to identify genes underlying inherited coloboma, significant inroads are being made into understanding the molecular events controlling closure of the optic fissure. In general, severity of disease can be linked to the temporal expression of the gene, but this is modified by factors such as tissue specificity of gene expression and genetic redundancy.

Animals↗
PubMed1988

Unknown syndrome: Hirschsprung's disease, microcephaly, and iris coloboma: a new syndrome of defective neuronal migration.

We describe three children with Hirschsprung's disease and microcephaly, two of whom also have an iris coloboma. Two of the children, one with a coloboma and one without, are from the same consanguineous pedigree. The third case is unrelated and was identified by the matching program of the London Dysmorphology Database. This is the first report of this combination of features which are considered to be secondary to defective neuronal migration. An autosomal recessive mode of inheritance is proposed.

Coloboma↗
PubMed2002

National study of microphthalmia, anophthalmia, and coloboma (MAC) in Scotland: investigation of genetic aetiology.

We report an epidemiological and genetic study attempting complete ascertainment of subjects with microphthalmia, anophthalmia, and coloboma (MAC) born in Scotland during a 16 year period beginning on 1 January 1981. A total of 198 cases were confirmed giving a minimum live birth prevalence of 19 per 100 000. One hundred and twenty-two MAC cases (61.6%) from 115 different families were clinically examined and detailed pregnancy, medical, and family histories obtained. A simple, rational, and apparently robust classification of the eye phenotype was developed based on the presence or absence of a defect in closure of the optic (choroidal) fissure. A total of 85/122 (69.7%) of cases had optic fissure closure defects (OFCD), 12/122 (9.8%) had non-OFCD, and 25/122 (20.5%) had defects that were unclassifiable owing to the severity of the corneal or anterior chamber abnormality. Segregation analysis assuming single and multiple incomplete ascertainment, respectively, returned a sib recurrence risk of 6% and 10% in the whole group and 8.1% and 13.3% in the OFCD subgroup. Significant recurrence risks were found in both unilateral and bilateral disease. In four families, one parent had an OFCD, two of which were new diagnoses in asymptomatic subjects. All recurrences in first degree relatives occurred in the OFCD group with a single first cousin recurrence seen in the non-OFCD group. A total of 84/122 of the MAC cases were screened for mutations in the coding regions of PAX6, CHX10, and SIX3. No pathogenic mutations were identified in the OFCD cases. A single PAX6 homeodomain missense mutation was identified in a subject with partial aniridia that had been initially misclassified as coloboma.

Anophthalmos↗
PubMed1994

Optic nerve coloboma (morning glory syndrome): CT findings.

This study demonstrates computed tomographic (CT) findings of morning glory syndrome. CT examination of the orbits was performed in three patients. Images of 2-mm-thick sections were acquired at 2-mm intervals without use of contrast material. Excellent demonstration of coloboma was achieved in each case. Because both magnetic resonance imaging and ultrasonography have limitations in imaging of coloboma, CT is the imaging method of choice in diagnosis of this disorder.

Child↗
PubMedDate not supplied

Bilateral congenital macular coloboma in a boy with Down syndrome.

PURPOSE: To describe macular coloboma in Down syndrome. METHODS: A 12-year-old boy with Down syndrome underwent ophthalmologic examination. RESULTS: The patient had a circumscribed, round defect about 1 disc diameter, with bared sclera at the base and pigment clump at the macula in both fundi. His poor visual acuity was unchanged since childhood. The results of serum IgG and IgM titers for Toxoplasma gondii were negative. CONCLUSIONS: Congenital macular coloboma associated with Down syndrome, as demonstrated in our patient, may not have occurred by chance.

Child↗
PubMed1992

Update of sporadic microphthalmos and coloboma. Non-inherited anomalies.

The majority of patients with microphthalmos and colobomas have genetic disorders. This is a survey of non-inherited, sporadic microphthalmos. Such cases may occur in the Goldenhar, CHARGE and VATER associations; it may also be due to teratological agents, for instance maternal ingestion of drugs, maternal infection, fever or irradiation. In these cases it is possible that neural crest cell development is abnormal. Some drugs, for instance retinoic acid are regulators of Hox genes which control an ordered sequence of differentiation; coloboma or microphthalmos may appear if deregulation occurs. Large choristomas of the anterior segment of the eye may be associated with microphthalmos or anophthalmos. Encephaloceles or orbital tumours may deform the growing eye and are another cause of non-inherited microphthalmos.

Abnormalities, Drug-Induced↗
PubMedDate not supplied

Infantile idiopathic hypercalciuria, high congenital myopia, and atypical macular coloboma: a new oculo-renal syndrome?

Four cases of infantile idiopathic hypercalciuria with high congenital myopia and atypical macular coloboma are discussed; two of them are brother and sister. The eye examination shows bilateral congenital myopia of more than 10 diopters in every case. In the fundus examination, there is a bilateral macular colobomatous lesion in two of them and monocular lesion in the remaining ones. Hypercalciuria is considered to be due to renal tubulus malformation. The macular atypical coloboma etiopathogenesis is discussed, with comment on the malformative, dystrophic and inflammatory hypothesis, having discarded the usual inflammatory etiologies. We have only found two cases similar to these in the literature, Given the relative scarce occurrence of each of the three mentioned clinical features we suggest the possibility of a new oculo-renal syndrome rather than a coincidental association.

Adolescent↗
PubMedDate not supplied

Symmetrical bilateral lens colobomas in two brothers.

True lens coloboma is a rare developmental disorder usually caused by missing lens zonules in the equatorial area of the lens. Bilateral cases are rare. We report bilateral superonasal lens colobomas in two brothers whose parents are first cousins.

Amblyopia↗
PubMed2000

Regional variation in blindness in children due to microphthalmos, anophthalmos and coloboma.

BACKGROUND: The prevalence and causes of blindness in children vary widely between regions. Few epidemiological data are available on the relative importance of the major congenital anomalies of the globe (i.e., microphthalmos, anophthalmos, coloboma) as causes of blindness in children. The aim of this study was to determine the re-gional variation in the proportion of severe visual impairment and blindness due to congenital abnormalities of the globe in children in schools for the blind and in those identified through Community Based Rehabilitation programs. Other objectives were to estimate the prevalence of blindness due to major congenital abnormalities, and to investigate their etiology. METHODS: Data on the causes of blindness in children were collected between 1990 and 1998 using standard methods, definitions and reporting form in 26 countries. Children were examined in schools for the blind and in Community Based Rehabilitation programs. RESULTS: Of 7,113 children aged 3-15 years with severe visual impairment and blindness examined, 762 (10.7%) had microphthalmos, 161 (2.3%) had anophthalmos, and 96 (1.3%) had coloboma. There are large regional differences in the proportion of severe visual loss in blind school children, ranging from 1.4% in Cuba to 33.2% in Sri Lanka. Severe visual loss due to congenital abnormalities of the globe is estimated to affect between 0.4 and 16.2/100,000 children in the countries studied. An underlying cause could not be identified in 84.2%. CONCLUSIONS: Major congenital abnormalities of the globe are important causes of severe visual loss in children, particularly in Asian countries. Further research into etiology is warranted in order to plan prevention programs.

Adolescent↗
PubMed2000

A new association of congenital hydrocephalus, albinism, megalocornea, and retinal coloboma in a syndromic child: a clinical and genetic study.

We describe a child with global developmental delay, prominent metopic suture, trigonocephaly, and cryptorchidism whose symptoms resemble the well-known 9p deletion syndrome or 9p monosomy. We also noted congenital hydrocephalus, oculocutaneous albinism, retinal coloboma, and megalocornea, which are not typical features of 9p monosomy. When a new albinism gene was localized to 9p (Chintamaneni et al., Biochem Biophys Res Commun 1991;178:227-235; Murty et al., Genomics 1992;13:227-229), we hypothesized that our patient had the 9p deletion syndrome plus albinism, with the deletion involving the albinism gene. We used FISH probes to test this hypothesis and found that the 9p region was normal, therefore excluding the 9p deletion syndrome. To our knowledge, the association of congenital hydrocephalus, albinism, megalocornea, and retinal coloboma has not been described in the literature. The purpose of this report is to describe this new association of congenital ocular and cerebral anomalies in a syndromic child.

Abnormalities, Multiple↗