Neuro-Ophthalmological Manifestations in Children with Down Syndrome: Current Perspectives

Oxidative stress biomarkers as novel screening tools for trisomy 21: a case-control study

OBJECTIVE

Oxidative stress plays a pivotal role in the pathogenesis of Down syndrome (Trisomy 21), as chromosome 21 harbors multiple genes involved in redox homeostasis and antioxidant defense mechanisms. This study aimed to evaluate the roles of transcription factors nuclear factor erythroid 2-related factor 2 (NRF2) and nuclear factor-kappa B (NFKB), along with antioxidant enzymes cystathionine-γ-lyase (CSE) and NAD(P)H dehydrogenase [quinone] 1 (NQO1) in amniotic fluid (AF) and maternal serum (MS) as potential biomarkers for prenatal screening of Down syndrome (DS).

METHODS

This prospective case-control study included singleton pregnant women undergoing amniocentesis between 16 and 24 weeks of gestation at Haseki Training and Research Hospital, Istanbul. Participants were divided into two groups: 28 pregnancies with DS confirmed by karyotype analysis (DS group) and 37 pregnancies with normal karyotype results (non-DS group). Amniotic fluid and maternal blood samples were analyzed using enzyme-linked immunosorbent assay (ELISA) kits to measure the levels of selected biomarkers.

RESULTS

NQO1 levels were significantly higher in the DS group compared to the non-DS group in both amniotic fluid (924.84 ± 475.94 vs. 505.62 ± 358.17 ng/ml, p < 0.001) and maternal serum (716.216 ± 242.91 vs. 394.87 ± 344.86 ng/ml, p < 0.001). NRF2 levels were significantly lower in the DS group in both amniotic fluid (3.77 ± 4.20 vs. 6.47 ± 5.53 ng/ml, p = 0.029) and maternal serum (7.54 ± 5.68 vs. 14.46 ± 16.53 ng/ml, p = 0.022).

CONCLUSION

The study highlights the importance of further research to validate the use of these antioxidant enzymes and transcription factors in non-invasive prenatal testing, which may reduce the need for invasive procedures and associated complications.

CLINICAL TRIAL NUMBER

Not applicable.

Corneal Collagen Cross-linking for Keratoconus in Pediatric and Developmentally Delayed Patients

PURPOSE

Corneal cross-linking (CXL) is the standard of care in patients with keratoconus but presents unique challenges in children and developmentally delayed patients. We present our clinical decision-making algorithm, CXL surgical technique, and outcomes in these groups.

METHODS

A retrospective chart review was undertaken at a tertiary referral center of all patients who underwent CXL for keratoconus at University of Pittsburgh Medical Center (UPMC) Children's Hospital of Pittsburgh between October 1, 2017, and April 1, 2021. Demographic information along with preoperative, intraoperative, and postoperative ophthalmic examination findings were collected. The main outcome measures were indications of CXL, postoperative complications, and visual acuity (VA).

RESULTS

Forty-eight eyes of 34 patients [21 patients (30 eyes) with developmental delay (DD) and 13 patients (18 eyes) with no DD (NDD)] underwent epithelium-off, standard CXL. General anesthesia was used for CXL in all patients except for 3 with NDD. A temporary central tarsorrhaphy was performed in all patients with DD and 7 patients with NDD. The remaining got a bandage contact lens. There were no immediate postoperative complications. A trend toward improvement in VA was noted postoperatively. The mean logMAR VA (with habitual correction) was 0.67 preoperatively and 0.57 postoperatively ( P = 0.3) in DD and 0.52 and 0.36, respectively ( P = 0.13), in NDD.

CONCLUSIONS

This retrospective review presents a technique for assessment and treatment of keratoconus in children and those with DD. Our technique ensures timely diagnosis and provides a safe method for CXL in these groups. Temporary central tarsorrhaphy is a well-tolerated option to reduce postoperative pain.

Prevalence and etiology of strabismus in Down syndrome: A systematic review and meta-analysis with a focus on ethnic differences in the esotropia/exotropia ratio

Purpose

We sought to determine the prevalence of strabismus and the esotropia/exotropia ratio in Down syndrome. Wide ranges of an increased strabismus prevalence have been reported and it is unclear by how much esotropia exceeds exotropia in people with Down syndrome.

Methods

We compiled in a systematic review and meta-analysis the results of over 100 studies that report the strabismus prevalence and ratio of esotropia/exotropia in cohorts of Down syndrome. We calculated the pooled global prevalence and established the geographical distribution of the strabismus prevalence and the esotropia/exotropia ratio.

Results

The ethnically-adjusted global prevalence of strabismus in Down syndrome is 30.2%. In subjects 15 years and older, the global prevalence is 53.2%, and the lifetime prevalence is 51.0%. In populations which normally have more esotropia than exotropia (e.g., Caucasians), Down syndrome subjects have a further increased bias towards esotropia. In populations which normally have more exotropia (e.g., West Africans, Asians and Hispanics), Down syndrome subjects have a significantly lower esotropia/exotropia ratio (3.21) than reported in Caucasians with Down syndrome (9.98).

Conclusion

Worldwide, about 1.81 million people with Down syndrome have strabismus: 1.42 million of them have esotropia, and 0.37 million have exotropia. Differences in the esotropia/exotropia ratio between ethnicities point to the orbital anatomy as a major contributing factor to the etiology of strabismus in Down syndrome. The narrow-set eyes (reduced orbital width) in Down syndrome favor esotropia over exotropia, especially in Caucasians, thus explaining why Down syndrome patients from different ethnicities have different prevalences of esotropia and exotropia.

Association of plasma neurofilament light chain with microstructural white matter changes in Down syndrome

INTRODUCTION

Both micro- and macrostructural white matter (WM) abnormalities, particularly those related to axonal degeneration, are associated with cognitive decline in adults with Down syndrome (DS) prior to a diagnosis of Alzheimer disease. Neurofilament light chain (NfL) is a support protein within myelinated axons released into blood following axonal damage. In this study we investigated cross-sectional relationships between WM microstructural changes as measured by diffusion tensor imaging (DTI) and plasma NfL concentration in adults with DS without dementia.

METHODS

Thirty cognitively stable (CS) adults with DS underwent diffusion-weighted MRI scanning and plasma NfL measurement. DTI measures of select WM tracts were derived using automatic fiber tracking, and associations with plasma NfL were assessed using Spearman correlation coefficients.

RESULTS

Higher Plasma NfL was associated with greater altered diffusion measures of select tracts.

DISCUSSION

Early increases in plasma NfL may reflect early white matter microstructural changes prior to dementia in DS.

Highlights

The onset of such WM changes in DS has not yet been widely studied.WM microstructural properties correlated with plasma neurofilament light chain (NfL).NfL may reflect early, selective WM changes in adults with DS at high risk of developing AD.

Trisomy 21 and Congenital Heart Disease: Impact on Health and Functional Outcomes From Birth Through Adolescence: A Scientific Statement From the American Heart Association

Due to improvements in recognition and management of their multisystem disease, the long-term survival of infants, children, and adolescents with trisomy 21 and congenital heart disease now matches children with congenital heart disease and no genetic condition in many scenarios. Although this improved survival is a triumph, individuals with trisomy 21 and congenital heart disease have unique and complex care needs in the domains of physical, developmental, and psychosocial health, which affect functional status and quality of life. Pulmonary hypertension and single ventricle heart disease are 2 known cardiovascular conditions that reduce life expectancy in individuals with trisomy 21. Multisystem involvement with respiratory, endocrine, gastrointestinal, hematological, neurological, and sensory systems can interact with cardiovascular health concerns to amplify adverse effects. Neurodevelopmental, psychological, and functional challenges can also affect quality of life. A highly coordinated interdisciplinary care team model, or medical home, can help address these complex and interactive conditions from infancy through the transition to adult care settings. The purpose of this Scientific Statement is to identify ongoing cardiovascular and multisystem, developmental, and psychosocial health concerns for children with trisomy 21 and congenital heart disease from birth through adolescence and to provide a framework for monitoring and management to optimize quality of life and functional status.

Vision Impairments in Young Adults with Down Syndrome

People with Down syndrome have more visual problems than the general population. They experience premature ageing, and they are expected to also have an acceleration in worsening visual function. A prospective observational study which includes visual acuity, refractive error, accommodation, binocular and colour vision was performed on young adults with (n = 69) and without (n = 65) Down syndrome and on a senior group (n = 55) without Down syndrome. Results showed significant differences in visual acuity between groups (p < 0.001), and it can be improved with a new prescription in 40% of the participants with Down syndrome. Regarding the accommodative state, no significant differences were found between groups of young people. Concerning binocular vision, 64.7% of strabismus was observed in the group with Down syndrome (p < 0.001). Visual abnormalities are significant in young adults with Down syndrome and are different from those of older people without Down syndrome, some of which can be improved by providing the optimal prescription as well as regular eye examinations.

Down syndrome: a review of ocular manifestations

Down syndrome is the most common genetically mediated intellectual disability. Although many physiologic and pathologic features of Down syndrome are discussed at length in the literature, the ocular manifestations of Down syndrome have seldom been discussed in a comprehensive fashion. Given that Down syndrome has ocular manifestations from the front to the back of the eye, it is important for physicians to become familiar with these manifestations, especially given the prevalence of Down syndrome. This review aims to discuss the varied ophthalmologic manifestations of Down syndrome – including strabismus, amblyopia, nystagmus, accommodation deficits, nasolacrimal duct obstruction, keratoconus, optic nerve pathology, neoplastic disease, and retinal pathology – to facilitate better care and visual outcomes in this important patient population.