Nationwide Incidence of Infantile Cataract Surgery and Risk of Secondary Glaucoma in a Population-based Birth Cohort

Truncation mutations of CRYGD gene in congenital cataracts cause protein aggregation by disrupting the structural stability of γD-crystallin

Congenital cataracts, a prevalent cause of blindness in children, are associated with protein aggregation. γD-crystallin, essential for sustaining lens transparency, exists as a monomer and exhibits excellent structural stability. In our cohort, we identified a nonsense mutation (c.451_452insGACT, p.Y151X) in the CRYGD gene. To explore the effect of truncation mutations on the structure of γD-crystallin, we examined the Y151X and T160RfsX8 mutations, both located in the Greek key motif 4 at the cellular and protein level in this study. Both truncation mutations induced protein misfolding and resulted in the formation of insoluble aggregates when overexpressed in HLE B3 and HEK 293T cells. Moreover, heat, UV irradiation, and oxidative stress increased the proportion of aggregates of mutants in the cells. We next purified γD-crystallin to estimate its structural changes. Truncation mutations led to conformational disruption and a concomitant decrease in protein solubility. Molecular dynamics simulations further demonstrated that partial deletion of the conserved domain within the Greek key motif 4 markedly compromised the overall stability of the protein structure. Finally, co-expression of α-crystallins facilitated the proper folding of truncated mutants and mitigated protein aggregation. In summary, the structural integrity of the Greek key motif 4 in γD-crystallin is crucial for overall structural stability.

Nationwide incidence of and risk factors for undergoing incisional glaucoma surgery following infantile cataract surgery

Nationwide incidence and risk factors for incisional glaucoma surgery post-infantile cataract (IC) surgery in children remain poorly understood. We conducted a population-based cohort study using the Korean national health claims database to identify IC patients diagnosed before age 1 who had IC surgery among all Korean born between 2008 and 2018 (n = 9,593,003). We estimated the annual occurrence of undergoing incisional glaucoma surgery following IC surgery in the general population aged 0-10. The risk factors for incisional surgery including systemic comorbidities and ophthalmic anomalies were analyzed by multivariable logistic regression. Of 650 patients who had undergone IC surgery with a mean (standard deviation [SD]) follow-up period of 6.2 (3.2) years, 92 (14.2%) were diagnosed with glaucoma following infantile cataract surgery (GFICS). Among them, 21 patients (22.8%) underwent incisional glaucoma surgery after a mean (SD) follow-up duration of 5.4 (2.8) years from the diagnosis of GFICS. Median (InterQuartile Range) age at incisional surgery was 4 (2,6) years old. Twenty of 21 patients (95.2%) underwent incisional glaucoma surgery within 3 years of diagnosis of GFICS. No factors, except younger age at glaucoma diagnosis (P = 0.03), were associated with undergoing incisional surgery. These findings can better understand the epidemiologic features and clinical courses of GFICS.

[Glaucoma in infancy and childhood]

Glaucoma in infancy and childhood is a rare disease. An immediate diagnosis and treatment are absolutely necessary to prevent blindness of affected children. Childhood glaucoma is characterized by a heterogeneous phenotype: besides primary congenital glaucoma, secondary types often exist and the individualized treatment requires an experienced interdisciplinary team. The pathogenesis is not always discernible and genetic alterations sometimes cause the disease. A surgical procedure is usually necessary to lower the intraocular pressure. Refractive and orthoptic care are equally important to avoid amblyopia. This article gives an overview of childhood glaucoma and outlines the most important diagnostic and therapeutic aspects.