Introduction: Non-acquired lens anomalies are rather rare diseases. However, they are a cause a significant visual impairment presenting at a young age and a major cause of amblyopia. Besides the ocular implications, these anomalies could be either isolated or associated with systemic disorders, thus warranting systemic evaluation once diagnosed.Ectopialentis (EL) is one of those anomalies that usually presents bilateral. Microspherophakia (MSP) is another lens anomaly where zonular development is defective, similar to ectopialentis, causing a smaller and spherical crystalline lens and thus causing lenticular myopia. Other less common lens anomalies include lenticonus, lentiglobus and lens coloboma. The biometric characteristics of the crystalline lens anomalies have always been a field of concern in research to provide a better understanding of the shape of eyes in such conditions and might aid in diagnosis as those conditions are rare but rather imperative to be recognized because of the sight threatening complications. Aim: The aim of this study was to report on the biometric characteristics of the anterior segment of children eyes with non-acquired abnormalities in the natural crystalline lens shape or position.
Purpose: To report the clinical and genetic study of two families of Egyptian origin with clinical anophthalmia. To further determine the role of the retina and anterior neural fold homeobox gene (RAX) in anophthalmia and associated cerebral malformations.Methods: Three patients with clinical anophthalmia and first-degree relatives from two consanguineous families of Egyptian origin underwent full ophthalmologic, general and neurologic examination, and blood tests. Cerebral magnetic resonance imaging (MRI) was performed in the index cases of both families. Genomic DNA was prepared from venous leukocytes, and direct sequencing of all the exons and intron-exon junctions of RAX was performed after PCR amplification.Results: Clinical bilateral anophthalmia was observed in all three patients. General and neurologic examinations were normal; obesity and delay in psychomotor development were observed in the isolated case. Orbital MRI showed a hypoplastic orbit with present but rudimentary extraocular muscles and normal lacrimal glands. Cerebral MRI showed agenesis of the optic nerves, optic tracts, and optic chiasma. In the index case of family A, the absence of the frontal and sphenoidal sinuses was also noted. In the index case of family B, only the sphenoidal sinus was absent, and there was significant cortical atrophy. The three patients carried a novel homozygous c.543+3A>G mutation (IVS2+3A>G) in RAX. Parents were healthy heterozygous carriers. No mutations were detected in orthodenticle homeobox 2 (OTX2), ventral anterior homeobox 1 (VAX1), or sex determining region Y-box 2 (SOX2).Conclusions: This is the first report of a homozygous splicing RAX mutation associated with autosomal recessive bilateral anophthalmia. To our knowledge, only two isolated cases of anophthalmia, three null and one missense case affecting nuclear localization or the DNA-binding homeodomain, have been found to be caused by compound heterozygote RAX mutations. A novel missense RAX mutation was identified in three patients with bilateral anophthalmia and a distinct systemic and neurologic phenotype. The mutation potentially affects splicing of the last exon and is thought to result in a protein that has an aberrant homeodomain and no paired-tail domain. Functional consequences of this change still need to be characterized.
Objective: To report a novel phenotype of autosomal dominant atypical congenital cataract associated with variable expression of microcornea, microphthalmia, and iris coloboma linked to chromosome 2. Molecular analysis of this phenotype may improve our understanding of anterior segment development.Design: Observational case study, genome linkage analysis, and gene mutation screening.Participants: Three families, 1 Egyptian and 2 Belgians, with a total of 31 affected were studied.Methods: Twenty-one affected subjects and 9 first-degree relatives underwent complete ophthalmic examination. In the Egyptian family, exclusion of PAX6, CRYAA, and MAF genes was demonstrated by haplotype analysis using microsatellite markers on chromosomes 11, 16, and 21. Genome-wide linkage analysis was then performed using 385 microsatellite markers on this family. In the 2 Belgian families, the PAX6 gene was screened for mutations by direct sequencing of all exons.Main Outcome Measures: Phenotype description, genome-wide linkage of the phenotype, linkage to the PAX6, CRYAA, and MAF genes, and mutation detection in the PAX6 gene.Results: Affected members of the 3 families had bilateral congenital cataracts inherited in an autosomal dominant pattern. A novel form of hexagonal nuclear cataract with cortical riders was expressed. Among affected subjects with available data, 95% had microcornea, 39% had microphthalmia, and 38% had iris coloboma. Seventy-five percent of the colobomata were atypical, showing a nasal superior location in 56%. A positive lod score of 4.86 was obtained at theta = 0 for D2S2309 on chromosome 2, a 4.9-Mb common haplotype flanked by D2S2309 and D2S2358 was obtained in the Egyptian family, and linkage to the PAX6, CRYAA, or MAF gene was excluded. In the 2 Belgian families, sequencing of the junctions and all coding exons of PAX6 did not reveal any molecular change.Conclusions: We describe a novel phenotype that includes the combination of a novel form of congenital hexagonal cataract, with variably expressed microcornea, microphthalmia, and atypical iris coloboma, not caused by PAX6 and mapping to chromosome 2.Financial Disclosure(s): The authors have no proprietary or commercial interest in any materials discussed in this article. Ophthalmology 2009;116:154-162 (C) 2009 by the American Academy of Ophthalmology.
Purpose: To report the clinical and genetic study of patients with autosomal dominant aniridia.Methods: We studied ten patients with aniridia from three families of Egyptian origin. All patients underwent full ophthalmologic, general and neurological examination, and blood drawing. Cerebral magnetic resonance imaging was performed in the index case of each family. Genomic DNA was prepared from venous leukocytes, and direct sequencing of all the exons and intron-exon junctions of the Paired Box gene 6 (PAX6) was performed after PCR amplification. Phenotype description, including ophthalmic and cerebral anomalies, mutation detection in PAX6 and phenotype-genotype correlation was acquired.Results: Common features observed in the three families included absence of iris tissue, corneal pannus with different degrees of severity, and foveal hypoplasia with severely reduced visual acuity. In Families 2 and 3, additional findings, such as lens dislocation, lens opacities or polar cataract, and glaucoma, were observed. We identified two novel (c. 170-174delTGGGC [p.L57fs17] and c. 475delC [p.R159fs47]) and one known (c.718C>T [p.R240X]) PAX6 mutations in the affected members of the three families. Systemic and neurological examination was normal in all ten affected patients. Cerebral magnetic resonance imaging showed absence of the pineal gland in all three index patients. Severe hypoplasia of the brain anterior commissure was associated with the p.L57fs17 mutation, absence of the posterior commissure with p.R159fs47, and optic chiasma atrophy and almost complete agenesis of the corpus callosum with p.R240X.Conclusions: We identified two novel PAX6 mutations in families with severe aniridia. In addition to common phenotype of aniridia and despite normal neurological examination, absence of the pineal gland and interhemispheric brain anomalies were observed in all three index patients. The heterogeneity of PAX6 mutations and brain anomalies are highlighted. This report emphasizes the association between aniridia and brain anomalies with or without functional impact, such as neurodevelopment delay or auditory dysfunction.
Methods Ten patients with aniridia from 3 families of Egyptian origin underwent full ophthalmologic, general and neurological examination, and blood drawing. Cerebral MRI was performed in the index case of each family. Genomic DNA was prepared from venous leukocytes and direct sequencing of all the exons and intron-exon junctions of the PAX6 gene was performed after PCR amplification. Results Common features observed in the three families included absence of iris tissue, corneal pannus with different degrees of severity and foveal hypoplasia with severely reduced visual acuity. In families 2 and 3, additional findings such as lens dislocation, lens opacities or polar cataract and glaucoma were observed. We identified two novel (c.170-174delTGGGC [p.L57fs17] and c.475delC [p.R159fs47]) and one known (c.718C>T) PAX6 mutations in the affected members of the 3 families. Systemic and neurological examination was normal in all ten affected patients. Cerebral MRI showed absence of the pineal gland in all three index patients. Severe hypoplasia of the brain anterior commissure was associated to the p.L57fs17mutation, absence of the posterior commissure to both p.R159fs47 and p.R240X, and optic chiasma atrophy and almost complete agenesis of the corpus callosum to p.R240X. Conclusions We identified two novel PAX6 mutations in families with severe aniridia from Northern Egypt, an ethnic group which is not well studied. In addition to common phenotype of aniridia and despite normal neurological examination, absence of the pineal gland was observed in all 3 index patients. The heterogeneity of brain anomalies related to PAX6 mutations is underexplored and is highlighted in this study.