Novel ADAMTSL4 gene mutations in Chinese patients with isolated ectopia lentis

Autosomal Recessive ADAMTSL4-Related Isolated Ectopia Lentis in the Ohio Old Order Amish and Mennonite Communities

Purpose: To present a series of 4 patients from the Ohio Amish or Mennonite populations with isolated ectopia lentis. Methods: A case series was evaluated. Results: Four cases with bilateral lens subluxations were diagnosed with a homozygous c.767_786del pathogenic variant in ADAMTSL4. Their ages ranged from 2 to 22 years. Three cases were symptomatic and were managed surgically with lensectomy, vitrectomy, and endolaser photocoagulation with or without secondary intraocular lens (IOL) implantation. One asymptomatic patient was observed. The postoperative visual acuity ranged from 20/20 to 20/60 in nonamblyopic eyes. Conclusions: The pathogenic homozygous c.767_786del variant in ADAMTSL4 may be a cause of bilateral isolated ectopia lentis in the Ohio Amish and Mennonite populations, likely as a result of a founder effect. Vitrectomy and lens extraction with or without secondary IOL implantation may lead to good visual outcomes. There were no cases of retinal detachment.

Clinical and Genetic Landscape of Ectopia Lentis Based on a Cohort of Patients From 156 Families

Purpose

To extend the mutation spectrum and explore the characteristics of genotypes and ocular phenotypes in ectopia lentis (EL).

Methods

Variants in all 14 reported EL-associated genes were selected from in-house data sets as well as literature review, and available clinical data were analyzed.

Results

Likely pathogenic variants in three genes were identified in 156 unrelated families with EL from the in-house cohort, of which 97.4% resulted from variants in FBN1, whereas the remaining were caused by variants in ADAMTSL4 (1.3%) and LTBP2 (1.3%). A comparative analysis of the in-house data and literature review suggested several characteristics: (1) a higher proportion of cysteine involvement variants in FBN1, either variants introducing or eliminating cysteine, and an earlier diagnosis age were presented in our cohort than in published literature; (2) the axial length (AL) and refractive error increased more rapidly with age in preschool EL children than normal children, and the increased rate of AL was slower in patients with surgery than those without surgery; (3) aberrant astigmatism was common in EL; and (4) worse vision and earlier onset age were observed in patients with non-FBN1 variants (all P < 0.05).

Conclusions

Variants in FBN1 are the predominant cause of EL, with the most common cysteine involvement variants. Early-stage EL manifests refractive error but gradually converts to axial myopia through defocus introduced by lens dislocation. Aberrant astigmatism is a suggestive sign of EL. Non-FBN1 variants cause early-onset and severe phenotypes. These results provide evidence for early diagnosis as well as timely treatment for EL.

A novel ADAMTSL4 compound heterozygous mutation in isolated ectopia lentis: a case report and review of the literature

BACKGROUND

Congenital ectopia lentis is characterized by dislocation of the lens caused by partial or complete abnormalities in the zonular fibers. It can be caused by either systemic diseases or isolated ocular diseases. Gene detection techniques can provide valuable information when an etiological diagnosis is challenging. Herein, we report the case of a six-year-old girl with a confirmed diagnosis of isolated ectopia lentis caused by a compound heterozygous ADAMTSL4 gene mutation.

CASE PRESENTATION

The patient was a 6-year-old Chinese Han girl with strabismus in the right eye. Slit lamp examination revealed that the lens in the right eye was opacified and dislocated, without an ectopic pupil. Gene detection demonstrated the presence of a compound heterozygous mutation in the ADAMTSL4 gene [c. 2270dupG (p.Gly758Trpfs *59) and c. 2110A > G (p.Ser704Gly)], and the diagnosis of isolated ectopia lentis was confirmed. She underwent lens extraction, and a sutured scleral-fixated posterior chamber intraocular lens (IOL) was placed in the right eye. The best-corrected visual acuity was 0.1 one month postoperatively.

CONCLUSION

Gene detection plays a crucial role in diagnosing disorders with similar symptoms, such as isolated ectopia lentis and Marfan syndrome. In this study, we used whole exons sequencing to diagnose isolated ectopia lentis and identified the variant c.2110A > G (p.Ser704Gly), which may be associated with the development of ectopia lentis and early-onset cataract in the patient. These pathogenic gene mutations have significant implications for the genetic diagnosis of congenital ectopia lentis, treatment, surveillance, and hereditary and prenatal counseling for the patient and their family members.

Visual prognosis and complications of congenital ectopia lentis: study protocol for a hospital-based cohort in Zhongshan Ophthalmic Center

INTRODUCTION

Congenital ectopia lentis (CEL) is a rare ocular disease characterised by the dislocation or displacement of the lens. Patients with mild lens dislocations can be treated with conservative methods (eg, corrective eyeglasses or contact lenses). In contrast, patients with severe CEL usually require surgical management. However, few studies have focused on the visual prognosis and complications in conservative and surgical management of patients. This study aims to investigate the prognosis and complications in patients with CEL with conservative and surgical management, which is vital for CEL management, especially the choice of surgical timing and surgical method.

METHODS AND ANALYSIS

A cohort study will be conducted at Zhongshan Ophthalmic Center. We plan to recruit 604 participants diagnosed with CEL and aged ≥3 years old. Patients with mild lens subluxation and stable visual conditions will be included in the non-surgical group and follow-up at 1, 2 and 3 years after enrolment. Patients with severe lens subluxation who accept CEL surgery will be included in the surgical group. Different surgical techniques, including phacoemulsification, in-the-bag intraocular lens implantation (with or without capsular tension ring) and trans-scleral fixation, will be used depending on the severity of dislocation. Patients will be followed up at 3 months, and 1, 2 and 3 years postoperatively. Over a 5-year follow-up period, patients will receive a detailed ocular examination, including optometry, biological measurement, specular microscopy, ultrasound biomicroscopy, anterior segment and posterior segment optical coherence tomography (OCT), OCT angiography, echocardiography and questionnaires on vision-related quality of life. The primary outcome is the change of best-corrected visual acuity and the incidence of complications in both groups.

ETHICS AND DISSEMINATION

Ethics approval was obtained from the ethics committee of the Zhongshan Ophthalmic Center (number: 2022KYPJ207). Study findings will be published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT05654025.

Metabolomic Profile in the Aqueous Humor of Congenital Ectopia Lentis

PURPOSE

To explore the metabolic profiles in the aqueous humor (AH) of patients with congenital ectopia lentis (CEL).

METHODS

We conducted a comprehensive analysis of the metabolites of AH samples of patients with CEL (n = 22) and age-matched patients (n = 22) with congenital cataract by ultra-high performance liquid chromatography tandem-mass spectrometry. The metabolomic characteristics were visualized by principal component analysis, orthogonal partial least squares discriminant analysis and heat map. The levels of the differential metabolites were also compared between CEL patients with and without FBN1 mutations. Pathway enrichment analysis was performed by using Kyoto Encyclopedia of Genes and Genomes. Receiver operating characteristic analysis was performed to select potential biomarkers.

RESULTS

There were 175 differential metabolites identified between the two groups. Eight metabolites were found to be potential biomarkers in AH of CEL patients. The CEL group showed a significant increase in α-ketoglutarate and decrease in citrate, suggesting that the tricarboxylic acid (TCA) cycle was disturbed. l-proline, prolyl-hydroxyproline, and l-histidine were reduced, which prompted enhanced degradation of microfibrils and collagen. Insidious retinal nerve damage was implied because N-Acetyl-aspartylglutamic acid and N-Acetyl-l-aspartic acid were found to be significantly increased. Pathway enrichment analysis indicated that disturbances in amino acid metabolism and carbohydrate metabolism were the key processes in the pathogenesis of CEL and that TCA cycle disorder may be the driving force behind disease occurrence.

CONCLUSION

These data reveal the characteristics in the metabolomic profiles of the AH of CEL patients, which help provide insights into the pathogenesis of this rare disease.

Mutation analysis of SUOX in isolated sulfite oxidase deficiency with ectopia lentis as the presenting feature: insights into genotype-phenotype correlation

Background

Isolated sulfite oxidase deficiency (ISOD) caused by sulfite oxidase gene (SUOX) mutations is a rare neurometabolic disease associated with ectopia lentis (EL). However, few genotype–phenotype correlations have been established yet.

Methods

Potentially pathogenic SUOX mutations were screened from a Chinese cohort of congenital EL using panel-based next-generation sequencing and analyzed with multiple bioinformatics tools. The genotype–phenotype correlations were evaluated via a systematic review of SUOX mutations within our data and from the literature.

Results

A novel paternal missense mutation, c.205G > C (p.A69P), and a recurrent maternal nonsense mutation, c.1200 C > G (p.Y400*), of SUOX were identified in a 4-year-old boy from 312 probands. The biochemical assays manifested elevated urine sulfite and S-sulfocysteine accompanied by decreased homocysteine in the blood. The patient had bilateral EL and normal fundus, yet minimal neurological involvement and normal brain structure. Molecular modeling simulation revealed the p.A69P mutant had an unstable structure but an unchanged affinity for sulfite, while the truncated p.Y400* mutant showed decreased binding capacity. Genotype–phenotype analysis demonstrated patients with biallelic missense mutations had milder symptoms (P = 0.023), later age of onset (P < 0.001), and a higher incidence of regression (P = 0.017) than other genotypes. No correlations were found regarding EL and other neurological symptoms.

Conclusion

The data from this study not only enrich the known mutation spectrum of SUOX but also suggest that missense mutations are associated with mild and atypical symptoms.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02544-x.

Correlation between novel compound heterozygous ADAMTSL4 variants and primary phenotypes of ectopia lentis et pupillae

PURPOSE

To investigate molecular pathogenesis of congenital ectopia lentis accompanied by various ophthalmic manifestations in a pedigree.

METHODS

Three female siblings, their spouse and offspring underwent ophthalmic and general medical examinations. Genetic variants were screened with the whole exome sequencing and analyzed in either a dominant or recessive inheritance manner. Gene mutations were ascertained with the Sanger sequencing after the polymerase chain reaction.

RESULTS

All three female siblings were diagnosed as the Ectopia lentis et pupillae (ELeP) through combination of clinical examination and genetic analysis. No characteristic pathological changes of skeletal, metabolic and cardiac abnormalities were observed. Thirteen genetic variants were selected out through analyzing in the dominant or recessive inheritance manner, but they were not associated with EL. Among them, ALOX15B variant may explain the skin disease in this pedigree. After inspection the known genes related to EL, novel compound heterozygous mutations (p.Ser264LeufsX37/p.Gly757ValfsX62) in ADAMTSL4 were discreetly identified in this ELeP pedigree.

CONCLUSIONS

Novel compound heterozygous ADAMTSL4 variants are responsible for ELeP in the current pedigree. Correlation between ADAMTSL4 variants and ELeP was firstly established based on our 12 years follow-up studies and previous reports of ELeP and of ADAMTSL4-related eye disorders. The primary phenotypes caused by ADAMTSL4 variants include EL, EP, poor pupillary dilation, and axial elongation. Highly varying phenotypes including glaucoma, high myopia retinapathy, and poor vision and so on may be the secondary impairments. All these secondary impairments may be improved if proper clinical interventions are implemented in time.