Visual outcome in patients with isolated autosomal dominant congenital cataract

Clinical and genetic characteristics of Chinese patients with familial or sporadic pediatric cataract

Background

Pediatric cataract is a clinically and genetically heterogeneous disease which is a significant cause of lifelong visual impairment and treatable blindness. Our study aims to investigate the genotype spectrum in a group of Chinese patients with pediatric cataract.

Methods

We enrolled 39 families with pediatric cataract from October 2015 to April 2016. DNA samples of the probands were analyzed by target next-generation sequencing. Variants were validated using Sanger sequencing in the probands and available family members.

Results

In our cohort of 39 cases with different types of pediatric cataract, 23 cases were found to harbor putative pathogenic variants in 15 genes: CRYAA, CRYBA1, CRYBA4, CRYBB1, CRYGC, CRYGD, MIP, GCNT2, IARS2, NHS, BCOR, BFSP2, FYCO1, MAF, and PAX6. The mutation detection rates in the familial and sporadic cases were 75 and 47.8%, respectively. Of the 23 causative variants, over half were novel.

Conclusions

This is a rare report of systematic mutation screening analysis of pediatric cataract in a comparably large cohort of Chinese patients. Our observations enrich the mutation spectrum of pediatric cataract. Next-generation sequencing provides significant diagnostic information for pediatric cataract cases, especially when considering sporadic and subtle syndromal cases.

Electronic supplementary material

The online version of this article (10.1186/s13023-018-0828-0) contains supplementary material, which is available to authorized users.

Personalized diagnosis and management of congenital cataract by next-generation sequencing

PURPOSE

To assess the utility of integrating genomic data from next-generation sequencing and phenotypic data to enhance the diagnosis of bilateral congenital cataract (CC).

DESIGN

Evaluation of diagnostic technology.

PARTICIPANTS

Thirty-six individuals diagnosed with nonsyndromic or syndromic bilateral congenital cataract were selected for investigation through a single ophthalmic genetics clinic.

METHODS

Participants underwent a detailed ophthalmic examination, accompanied by dysmorphology assessment where appropriate. Lenticular, ocular, and systemic phenotypes were recorded. Mutations were detected using a custom-designed target enrichment that permitted parallel analysis of 115 genes associated with CC by high-throughput, next-generation DNA sequencing (NGS). Thirty-six patients and a known positive control were tested. Suspected pathogenic variants were confirmed by bidirectional Sanger sequencing in relevant probands and other affected family members.

MAIN OUTCOME MEASURES

Molecular genetic results and details of clinical phenotypes were identified.

RESULTS

Next-generation DNA sequencing technologies are able to determine the precise genetic cause of CC in 75% of individuals, and 85% patients with nonsyndromic CC were found to have likely pathogenic mutations, all of which occurred in highly conserved domains known to be vital for normal protein function. The pick-up rate in patients with syndromic CC also was high, with 63% having potential disease-causing mutations.

CONCLUSIONS

This analysis demonstrates the clinical utility of this test, providing examples where it altered clinical management, directed care pathways, and enabled more accurate genetic counseling. This comprehensive screen will extend access to genetic testing and lead to improved diagnostic and management outcomes through a stratified medicine approach. Establishing more robust genotype-phenotype correlations will advance knowledge of cataract-forming mechanisms.

Frequency and predictors of retinal detachment after pediatric cataract surgery without primary intraocular lens implantation

PURPOSE

To determine the frequency and to identify predictors of retinal detachment after pediatric cataract surgery without primary intraocular lens implantation.

METHODS

Retrospective review at an eye hospital identified 1017 eyes among 579 patients who underwent limbal-approach surgery without primary IOL implantation at age < or =16 years for cataract unassociated with other ocular abnormalities aside from microcornea. Patients had a minimum of 2 years postoperative follow-up. The outcome measure was the presence or absence of postcataract surgery retinal detachment, and analyses were performed on patients' eyes with adjustment for intrasubject correlation.

RESULTS

Mean postcataract surgery follow-up was 6.8 +/- 3.6 years (range, 2.0 to 18.3 years). Retinal detachment developed in 33 (3.2%) of the 1017 patients' eyes and was diagnosed at a mean of 6.8 +/- 4.4 years postcataract surgery (range, 0.4 to 14.8 years). Multivariable Cox proportional hazards regression analysis with adjustment for intrasubject correlation identified an aphakic refractive error more myopic than the age-adjusted aphakic norm [hazard ratio (HR), 5.9; 95% confidence interval (CI), 1.9 to 18.0; P = 0.002] and postcataract surgery wound dehiscence (HR, 15.4; 95% CI, 2.2 to 108.5; P = 0.006) as predictors of retinal detachment; a primary posterior capsulotomy/anterior vitrectomy procedure was not predictive of retinal detachment.

CONCLUSIONS

Retinal detachment is infrequent following pediatric cataract surgery without primary IOL implantation, at least with short-term follow-up. A postoperative aphakic refractive error more myopic (less hyperopic) than the age-adjusted aphakic norm is predictive of this complication.

Visual impairment in children born at full term from 1972 through 1989 in Finland

OBJECTIVE

To investigate the incidence, prevalence, and causes of visual impairment in children born at full term and to determine conditions and factors associated with visual impairment.

DESIGN

Retrospective, cross-sectional, population-based study.

PARTICIPANTS

All visually impaired individuals from 0 to 17 years of age who were born at full term from 1972 through 1989 in Finland and recorded in the Finnish Register of Visual Impairment (n = 556) were eligible for this study.

METHODS

Data in the Finnish Register of Visual Impairment relating to 556 subjects were supplemented with data from hospital records and other national registers (Register of Births, Register of Congenital Malformations, Finnish Care Register, and Finnish Cancer Register). Data relating to the children born at full term were compared with Finnish perinatal and vital statistics and with data concerning children born prematurely. The chi-square test (Mantel-Haenszel) and stepwise logistic regression analysis were used in statistical analysis of the data.

MAIN OUTCOME MEASURES

Visual acuity, time of onset of visual impairment, ophthalmic diagnosis of visual impairment, systemic disease, multiple handicap, 5-minute Apgar score, prenatal disorders, perinatal disorders, disorders arising during infancy and childhood, and treatment.

RESULTS

Four hundred thirty-one of the 556 individuals with visual impairment (78%) had been born at full term. Visual impairment was predominantly associated with genetic (53%) and prenatal (34%) factors. Ocular malformations (34%), retinal diseases (31%), and neuro-ophthalmologic disorders (26%) were the main ophthalmic diagnoses. Optic nerve atrophy (20%) and congenital cataract (13%) were the most common single diagnoses. The occurrence of blindness, systemic disease, and multiple handicap was 40%, 43%, and 45%, respectively.

CONCLUSIONS

The incidence of visual impairment in children born at full term did not decline during the 2 decades covered by this study. The findings reflected the lack of treatment for genetic eye diseases. The results also confirmed an obvious need for further understanding of mechanisms underlying congenital anomalies of the human visual system.

Molecular genetic basis of inherited cataract and associated phenotypes

Congenital cataract is a leading cause of visual disability in children. Inherited isolated (non-syndromic) cataract represents a significant proportion of cases and recently many causative genetic mutations have been identified. Inherited cataract is known to be clinically and genetically heterogeneous. Eleven clear-cut cataract phenotypes have been described. Cataract may be inherited as autosomal dominant, autosomal recessive, or X-linked recessive traits, and 12 loci and 15 specific genes associated with inherited isolated cataract have been identified to date; it is likely that more genes remain to be discovered. The identification of remaining genes will not only improve our understanding of the mechanism of cataract formation but will shed new light on the developmental biology and biochemistry of the lens. Furthermore, it is possible that some of these genes will be implicated in the more common age related cataract, which also has a genetic component to its etiology.

Genetics of childhood cataract

PURPOSE OF REVIEW

Congenital cataracts, although much less common than their age-related counterparts, account for one-tenth of cases of childhood blindness. Approximately half are inherited, either in isolation or as part of a syndrome of ocular or systemic anomalies. This article reviews recent advances made in understanding the molecular genetic basis of isolated, nonsyndromic inherited cataract.

RECENT FINDINGS

New disease-causing mutations continue to be identified and now encompass genes encoding a wide variety of different lens proteins. More detailed investigations of the functional consequences of each mutation are being reported and suggest that lens opacification results not only from precipitation and amyloid-like accumulation of proteins essential for lens transparency but also from interference with their secondary functions.

SUMMARY

Improved functional characterization of mutations causing childhood cataract will improve understanding of lens development and physiology but will also have implications for the more common age-related cataract. This too has a significant genetic component to its etiology, and genes causing monogenic forms of childhood inherited cataract represent excellent candidate genes for age-related cataract. The identification of the genes conferring increased risk of developing age-related cataract will bring closer the development of a medical treatment to delay the onset of lens opacification and need for surgery.

Frequency and predictors of glaucoma after pediatric cataract surgery

PURPOSE

To determine the frequency of and identify predictors of chronic glaucoma after pediatric cataract surgery.

DESIGN

Interventional case series.

METHODS

Retrospective review at an eye hospital identified 570 eyes among 322 patients who underwent limbal-approach surgery without intraocular lens implantation at age <or=16 years for cataract unassociated with other ocular anomalies aside from microcornea. Patients had a minimum of 5 years' postoperative follow-up, which included intraocular pressure measurement. The outcome measure was the presence or absence of postcataract surgery glaucoma, defined as intraocular pressure >or=26 mm Hg, as measured on at least two occasions.

RESULTS

Mean follow-up was 9.0 +/- 3.1 years (median, 8.1 years; range, 5.0-18.3 years). Glaucoma developed in 118 of 570 patients' eyes (21%), including 101 of 272 (37%) undergoing surgery at <or=9 months of age and 17 of 298 (6%) undergoing surgery thereafter. Multivariable Cox proportional hazards regression analysis with adjustment for potential intrasubject correlation identified surgery at <or=9 months of age (hazard ratio [HR], 3.8; 95% confidence interval [CI], 1.8-7.7; P <.001), secondary membrane surgery (HR, 2.6; 95% CI, 1.3-5.3; P =.006), microcornea (HR, 1.9; 95% CI, 1.2-3.1; P =.008), and primary posterior capsulotomy/anterior vitrectomy (HR, 10.7; 95% CI, 1.4-80.6; P =.02) as predictors of glaucoma.

CONCLUSIONS

Chronic glaucoma is common after cataract surgery performed at or before, but not after, a certain age in childhood. The data suggest that this age threshold is 9 months, but a true threshold occurring at a somewhat later age cannot be fully excluded.

The morphology and natural history of childhood cataracts

The morphology of congenital cataract reflects a combination of the timing and nature of the cause, the anatomy of the lens including its capsule, its development, and changes that take place with time. Morphology may variably affect prognosis, give a clue to the etiology and the age of onset and, in an isolated case, sometimes suggest heritability. The spectrum of morphological variations is enormous and can be complex. A comprehensive approach is to classify the variations according to the area of the lens involved, and sub-dividing them by a detailed description of the shape and appearance. Each specific morphological type is then analyzed determining the etiology, visual prognosis, and management. The use of gene markers has allowed many of these variations to be identified and categorized. Cataracts in childhood can involve the whole lens, in which case they are called total, Morgagnian, or disk-like. They can affect only the center of the lens: lamellar, nuclear, oil droplet, cortical, or coronary. They can be anterior: anterior polar, anterior subcapsular, or anterior lenticonus. The posterior aspect of the lens can also be affected in different fashions: Mittendorf's dot, posterior lenticonus, posterior cortical cataracts, or posterior subcapsular. There are five more forms that must be described separately: punctuate lens opacities, sutural cataracts, coralliform or crystalline, wedge-shaped, and persistent hyperplastic primary vitreous.

Changes in visual acuity from 4 to 12 years of age in children operated for bilateral congenital cataracts

AIMS

To investigate the long term effects of age at surgery on the development of visual acuity (VA) by measuring VA from preschool age to puberty. Furthermore, to report the VA levels at 12 years of age in a geographically based cohort of operated congenital bilateral cataracts.

METHODS

All children born in four western counties of Sweden between January 1980 and December 1993 who were diagnosed with congenital cataracts were included in a longitudinal prospective study. The monocular VA of the better eye in 38 subjects was analysed at 4, 7, 10, and 12 years of age, with 20 total and 18 partial cataracts. The mean follow up time was 9.3 years after surgery.

RESULTS

The final value of VA was 0.4 or above for approximately 50% of the subjects at 12 years of age. Visual acuity improved to a considerable extent after school age, especially in children who underwent surgery between the ages of 7 weeks and 1 year. Results for partial cataracts were favourable compared to those for total cataracts, reaching a mean of approximately 0.5 at age 12. The mean VA in the group of total congenital cataracts operated on before 7 weeks of age achieved higher values of VA at 4 years of age compared to children with total cataracts operated on between 7 weeks and 1 year of age. However, no statistically significant difference in VA results among these groups could be proved.

CONCLUSION

Visual acuity improves to a considerable extent after school age in children with delayed visual development caused by congenital cataracts. Surgery within 7 weeks results in a more rapid development of VA, initially.