RESUMO
This study investigated the association between apolipoprotein E (APOE) gene polymorphisms (rs429358 and rs7412) and primary angle-closure glaucoma (PACG) and pseudoexfoliation glaucoma (PXG) in a Saudi cohort. Genotyping of 437 DNA samples (251 controls, 92 PACG, 94 PXG) was conducted using PCR-based Sanger sequencing. The results showed no significant differences in the allele and genotype frequencies of rs429358 and rs7412 between the PACG/PXG cases and controls. Haplotype analysis revealed ε3 as predominant, followed by ε4 and ε2 alleles, with no significant variance in PACG/PXG. However, APOE genotype analysis indicated a significant association between ε2-carriers and PACG (odds ratio = 4.82, 95% CI 1.52-15.26, p = 0.007), whereas no notable association was observed with PXG. Logistic regression confirmed ε2-carriers as a significant predictor for PACG (p = 0.008), while age emerged as significant for PXG (p < 0.001). These findings suggest a potential role of ε2-carriers in PACG risk within the Saudi cohort. Further validation and larger-scale investigations are essential to elucidate the precise role of APOE in PACG pathogenesis and progression.
Assuntos
Apolipoproteína E2 , Predisposição Genética para Doença , Glaucoma de Ângulo Fechado , Polimorfismo de Nucleotídeo Único , Feminino , Humanos , Masculino , Alelos , Apolipoproteína E2/genética , Estudos de Casos e Controles , Frequência do Gene , Genótipo , Glaucoma de Ângulo Fechado/genética , Haplótipos , Heterozigoto , Fatores de Risco , Arábia Saudita/epidemiologiaRESUMO
In this review, we outline our current understanding of the mechanisms involved in the absorption, storage, and transport of dietary vitamin A to the eye, and the trafficking of rhodopsin protein to the photoreceptor outer segments, which encompasses the logistical backbone required for photoreceptor cell function. Two key mechanisms of this process are emphasized in this manuscript: ocular and systemic vitamin A membrane transporters, and rhodopsin transporters. Understanding the complementary mechanisms responsible for the generation and proper transport of the retinylidene protein to the photoreceptor outer segment will eventually shed light on the importance of genes encoded by these proteins, and their relationship on normal visual function and in the pathophysiology of retinal degenerative diseases.
Assuntos
Rodopsina , Vitamina A , Rodopsina/metabolismo , Rodopsina/genética , Humanos , Vitamina A/metabolismo , Animais , Células Fotorreceptoras de Vertebrados/metabolismo , Células Fotorreceptoras/metabolismo , Transporte BiológicoRESUMO
Adult-onset glaucoma, an age-related neurodegenerative disease, is very prevalent among the elderly Arabs of Saudi origin. This study investigated the association between apolipoprotein E (APOE) gene variants (rs429358 and rs7412) and primary open-angle glaucoma (POAG) in Arabs of Saudi origin. A case-control genetic association study involving 179 POAG patients and 251 controls utilized Sanger sequencing to genotype APOE gene variants. The allele frequencies and genotype distributions for rs429358 and rs7412 did not show significant associations with POAG. The haplotype analysis revealed apoε3 (87.6% and 87.4%) as the most prevalent, followed by ε4 (2.8% and 3.6%) and ε2 (9.6% and 8.9%) in the controls and POAG patients, respectively. Although the ε2/ε3 genotype and ε2-carriers displayed a more than two-fold increased risk, statistical significance was not reached. Notably, these polymorphisms did not affect clinical markers, such as intraocular pressure and cup/disc ratio. The logistic regression analysis demonstrated no significant influence of age, sex, rs429358, or rs7412 polymorphisms on POAG. In conclusion, within the Saudi cohort, APOE variants (rs429358 and rs7412) do not appear to be associated with POAG and are not substantial risk factors for its development. However, additional population-based studies are required to validate these findings.
RESUMO
The genetic etiology of Keratoconus (KC) in Middle Eastern Arabs of Saudi origin is still unclear. A recent genome-wide study identified two significant loci in the region of PNPLA2 (rs61876744) and CSNK1E (rs138380) for KC that may be associated with KC in the Saudi population. In addition, polymorphisms in the apolipoprotein E (APOE) gene, namely, rs429358 and rs7412, responsible for APOE allelic variants ε2, ε3, and ε4, may influence KC via oxidative stress mechanism(s). Thus, we investigated the possible association of polymorphisms rs61876744, rs138380, rs429358, rs7412, and APOE genotypes in KC patients of the Saudi population. This study included 98 KC cases and 167 controls. Polymorphisms rs6187644 and rs138380 were genotyped using TaqMan assays, and rs429358 and rs7412 were genotyped via Sanger sequencing. Although the allele frequency of rs61876744(T) in PNPLA2 was a protective effect against KC (odds ratio (OR) = 0.64, 95% confidence interval (CI) = 0.44-0.93), the p-value (p = 0.020) was not significant for multiple testing correction (p = 0.05/4 = 0.015). However, rs6187644 genotype showed a modestly significant protective effect in the dominant model (OR = 0.53, 95% CI = 0.32-0.88, p = 0.013). Polymorphisms rs138380, rs429358, and rs7412 showed no significant allelic or genotype association with KC. However, the ε2-carriers (ε2/ε2 and ε2/ε3 genotypes) exhibited a greater than 5-fold increased risk of KC, albeit non-significantly (p = 0.055). Regression analysis showed no significant effect of age, gender, and the four polymorphisms on KC. Our results suggest that polymorphism rs6187644 in PNPLA2 might be associated with KC in the Middle Eastern Arabs of Saudi origin but warrant a large-scale association analysis at this locus.