Analysis of axial length in young patients with Marfan syndrome and bilateral ectopia lentis by Z-scores

Genotype-phenotype Correlations of Ocular Posterior Segment Abnormalities in Marfan Syndrome

Purpose

Marfan syndrome (MFS) is a connective tissue disorder caused by mutations in the fibrillin-1 ( (FBN1). In addition to typical phenotypes such as ectopia lentis (EL) and aortic dilation, patients with MFS are prone to ocular posterior segment abnormalities, including retinal detachment (RD), maculopathy, and posterior staphyloma (PS). This study aims to investigate the correlations between FBN1 genotype and posterior segment abnormalities within a Chinese cohort of MFS.

Design

Retrospective study.

Participants

One hundred twenty-one eyes of 121 patients with confirmed FBN1 mutations between January 2015 and May 2023 were included.

Methods

Comprehensive ophthalmic examination findings were reviewed, and the incidence of RD, atrophic, tractional, and neovascular maculopathy (ATN classification system), and PS was analyzed between different genotype groups. Only the more severely affected eye from each patient was included.

Main Outcome Measures

Clinical features and risk factors.

Results

Of 121 patients, 60 eyes (49.59%) exhibited posterior segment abnormalities, including RD (4, 3.31%), maculopathy (47, 38.84%), and PS (54, 44.63%). The mean age was 11.53 ± 11.66 years, with 79.34% of patients <20 years old. The location and region of mutations were found to be associated with the incidence of maculopathy (P = 0.013, P = 0.033) and PS (P = 0.043, P = 0.036). Mutations in the middle region had a lower incidence of maculopathy and PS (P = 0.028 and P = 0.006, respectively) than those in C-terminal region. Mutations in the transforming growth factor-β (TGF-β) regulating sequence exhibited a higher incidence of maculopathy and PS (P = 0.020, P = 0.040). Importantly, the location and region of mutations were also associated with the incidence of atrophic maculopathy (P = 0.013 and P = 0.033, respectively). Mutations in the middle region had a significantly lower probability of atrophic maculopathy (P = 0.006), while mutations in the TGF-β regulating region had a higher incidence of atrophic maculopathy (P = 0.020).

Conclusions

Maculopathy and PS were associated with the location and region of FBN1 mutations. Patients with mutations in the TGF-β regulating region faced an increased risk of developing retinopathy.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Influencing factors of effective lens position in patients with Marfan syndrome and ectopia lentis

AIMS

The aim of this study was to analyse the effective lens position (ELP) in patients with Marfan syndrome (MFS) and ectopia lentis (EL).

METHODS

Patients with MFS undergoing lens removal and primary intraocular lens (IOL) implantation were enrolled in the study. The back-calculated ELP was obtained with the vergence formula and compared with the theoretical ELPs. The back-calculated ELP and ELP error were evaluated among demographic and biometric parameters, including axial length (AL), corneal curvature radius (CCR) and white-to-white (WTW).

RESULTS

A total of 292 eyes from 200 patients were included. The back-calculated ELP was lower in patients undergoing scleral-fixated IOL than those receiving in-the-bag IOL implantation (4.54 (IQR 3.65-5.20) mm vs 4.98 (IQR 4.56-5.67) mm, p<0.001). The theoretical ELP of the SRK/T formula exhibited the highest accuracy, with no difference from the back-calculated ELP in patients undergoing in-the-bag IOL implantation (5.11 (IQR 4.83-5.65) mm vs 4.98 (IQR 4.56-5.67) mm, p=0.209). The ELP errors demonstrated significant correlations with refraction prediction error (PE): a 1 mm ELP error led to PE of 2.42D (AL<22 mm), 1.47D (22 mm≤AL<26 mm) and 0.54D (AL≥26 mm). Multivariate analysis revealed significant correlations of ELP with AL (b=0.43, p<0.001), CCR (b=-0.85, p<0.001) and WTW (b=0.41, p=0.004).

CONCLUSION

This study provides novel insights into the origin of PE in patients with MFS and EL and potentially refines existing formulas.

Predicting Marfan Syndrome in Children With Congenital Ectopia Lentis: Development and Validation of a Nomogram

Purpose

To derive an effective nomogram for predicting Marfan syndrome (MFS) in children with congenital ectopia lentis (CEL) using regularly collected data.

Methods

Diagnostic standards (Ghent nosology) and genetic test were applied in all patients with CEL to determine the presence or absence of MFS. Three potential MFS predictors were tested and chosen to build a prediction model using logistic regression. The predictive performance of the nomogram was validated internally through time-dependent receiver operating characteristic curves, calibration curves, and decision curve analysis.

Results

Eyes from 103 patients under 20 years old and with CEL were enrolled in this study. Z score of body mass index (odds ratio [OR] = 0.659; 95% confidence interval [CI], 0.453-0.958), corneal curvature radius (OR = 3.397; 95% CI, 1.829-6.307), and aortic root diameter (OR = 2.342; 95% CI, 1.403-3.911) were identified as predictors of MFS. The combination of the above predictors shows good predictive ability, as indicated by area under the curve of 0.889 (95% CI, 0.826-0.953). The calibration curves showed good agreement between the prediction of the nomogram and the actual observations. In addition, decision curve analysis showed that the nomogram was clinically useful and had better discriminatory power in identifying patients with MFS. For better individual prediction, an online MFS calculator was created.

Conclusions

The nomogram provides accurate and individualized prediction of MFS in children with CEL who cannot be identified with the Ghent criteria, enabling clinicians to personalize treatment plans and improve MFS outcomes.

Translational Relevance

The prediction model may help clinicians identify MFS in its early stages, which could reduce the likelihood of developing severe symptoms and improve MFS outcomes.

Predicting axial length in patients with Marfan syndrome and ectopia lentis after modified capsular tension ring and intraocular lens implantation

PURPOSE

To predict the growth of axial length (AL) in patients with Marfan syndrome (MFS) and ectopia lentis (EL).

SETTING

Eye and ENT Hospital of Fudan University, Shanghai, China.

DESIGN

Consecutive retrospective case series.

METHODS

Eyes were evaluated that had modified capsular tension ring and intraocular lens (IOL) implantation. The rate of AL growth (RALG) was calculated using AL divided by log10-transformed age. A multivariate linear regression model of RALG was developed after validation.

RESULTS

128 patients with MFS and EL were enrolled with a median follow-up duration of about 3 years. RALG was independent of age between 3 years and 15 years old ( P = .799) and decreased to 0 thereafter ( P = .878). Preoperative AL was associated with RALG in patients under 15 years old ( P = .003). Beta values for the final model of RALG were as below: intercept (-9.794) and preoperative AL (0.664). The postoperative AL was predicted as: postAL = preAL + RALG × log 10 ([postAge + 0.6]/[preAge + 0.6]). The mean prediction error was -0.003 (95% CI, -0.386 to 0.3791) mm and the mean absolute percentage error was 1.93% (95% CI, 0.73% to 3.14%). A Python-based calculator was developed to use the predicted AL in selecting IOL power and setting undercorrection.

CONCLUSIONS

The AL growth of patients with MFS followed a logarithmic pattern and ceased at about age 15. A prediction model of postoperative AL was established for individual MFS patients between 3 and 15 years old, which could potentially optimize the IOL power selection.

What Should We Pay More Attention to Marfan Syndrome Expecting Ectopia Lentis: Incidence and Risk Factors of Retinal Manifestations

(1) Background: This paper investigates the incidence and risk factors of retinal manifestations in patients with Marfan syndrome (MFS) in a Chinese cohort. (2) Methods: This is a population-based cross-sectional study. In total, 344 eyes (172 MFS participants) were enrolled, each of whom underwent a detailed ocular examination. B-scan ultrasonography, ultra-wide-angle fundus images and optical coherence tomography images were conducted to assess posterior staphyloma, types of retinal damages and maculopathy. (3) Results: MFS patients have a high proportion (32.5%) of maculopathy, among which atrophy is the most common type (27.6%). Compared with participants without maculopathy, participants with maculopathy had a longer axial length (AL), higher incidence of posterior staphyloma, macular split and retinal detachment (RD) (p < 0.001, p < 0.001, p < 0.001 and p = 0.001). Moreover, the stage of RD has a significant correlation with longer AL and shallower anterior chamber depth (ACD) (p = 0.001 and p = 0.034, respectively). (4) Conclusions: A higher incidence and earlier onset of fundus lesions were found in MFS patients. Yearly systematic examination is recommended for MFS children with fundus manifestation until the cardiovascular and skeletal development is complete.

Biallelic ADAMTSL4 variants in a Chinese cohort of congenital ectopia lentis: Implications for genotype-phenotype relationships

ADAMTSL4 variants are one of the common causes of congenital ectopia lentis (EL), reported ocular comorbidities of which include iris anomalies, cataract, and glaucoma. However, a genotype-phenotype correlation has not been established. Potentially pathogenic ADAMTSL4 variants were screened from a Chinese cohort of congenital EL using panel-based next-generation sequencing followed by multiple bioinformatics analyses. The genotype-phenotype correlation was assessed via a systematic review of ADAMTSL4 variants within our data and those from the literature. A total of 12 variants of ADAMTSL4, including seven frameshift variants, one nonsense variant, two splicing variants, and two missense variants, were found in nine probands. Combing genetic and clinical information from 72 probands in the literature revealed 37 ADAMTSL4 variants known to cause EL, and the ethnic difference was prominent. The lens was inclined to dislocate inferior temporally (22, 27.16%), while the pupil was always located oppositely (9, 81.82%). Several anterior segments anomalies were identified, including ectopia pupillae (15, 18.52%), persistent pupillary membrane (9, 11.10%), poor pupil dilation (4, 30.8%), cataract (13, 24.10%), and glaucoma (8, 13.33%). Genotype-phenotype analysis revealed that truncation variants had higher risks of combined iris anomalies, including either ectopia pupillae or a persistent pupillary membrane (p =  0.007). The data from this study not only extend our knowledge of the ADAMTSL4 variant spectrum but also suggest that deleterious variants of ADAMTSL4 might be associated with severe ocular phenotypes.

Genotype-phenotype correlations of marfan syndrome and related fibrillinopathies: Phenomenon and molecular relevance

Marfan syndrome (MFS, OMIM: 154700) is a heritable multisystemic disease characterized by a wide range of clinical manifestations. The underlying molecular defect is caused by variants in the FBN1. Meanwhile, FBN1 variants are also detected in a spectrum of connective tissue disorders collectively termed as ‘type I fibrillinopathies’. A multitude of FBN1 variants is reported and most of them are unique in each pedigree. Although MFS is being considered a monogenic disorder, it is speculated that the allelic heterogeneity of FBN1 variants contributes to various manifestations, distinct prognoses, and differential responses to the therapies in affected patients. Significant progress in the genotype–phenotype correlations of MFS have emerged in the last 20 years, though, some of the associations were still in debate. This review aims to update the recent advances in the genotype-phenotype correlations of MFS and related fibrillinopathies. The molecular bases and pathological mechanisms are summarized for better support of the observed correlations. Other factors contributing to the phenotype heterogeneity and future research directions were also discussed. Dissecting the genotype-phenotype correlation of FBN1 variants and related disorders will provide valuable information in risk stratification, prognosis, and choice of therapy.

Correlation between FBN1 mutations and ocular features with ectopia lentis in the setting of Marfan syndrome and related fibrillinopathies

Mutations of fibrillin-1 (FBN1) have been associated with Marfan syndrome and pleiotropic connective tissue disorders, collectively termed as "type I fibrillinopathy". However, few genotype-phenotype correlations are known in the ocular system. Patients with congenital ectopia lentis (EL) received panel-based next-generation sequencing, complemented with multiplex ligation-dependent probe amplification. In a total of 125 probands, the ocular phenotypes were compared for different types of FBN1 mutations. Premature termination codons were associated with less severe EL and a thinner central corneal thickness (CCT) than the inframe mutations. The eyes of patients with mutations in the C-terminal region had a higher incidence of posterior staphyloma than those in the middle and N-terminal regions. Mutations in the TGF-β-regulating sequence had larger horizontal corneal diameters (white-to-white [WTW]), higher incidence of posterior staphyloma, but less severe EL than those with mutations in other regions. Mutations in the neonatal region were associated with thinner CCT. Longer axial length (AL) was associated with mutations in the C-terminal region or TGF-β regulating sequence after adjusting for age, EL severity, and corneal curvature radius. FBN1 genotype-phenotype correlations were established for some ocular features, including EL severity, AL, WTW, CCT, and so forth, providing novel perspectives and directions for further mechanistic studies.