The association between genetic polymorphism of glutathione peroxidase 1 (rs1050450) and keratoconus in a Turkish population / A associação entre o polimorfismo genético da glutationa-peroxidase 1 (rs1050450) e pacientes com ceratocone em uma população turca

ABSTRACT Purpose: To investigate the potential associations between keratoconus and catalase rs1001179, superoxide dismutase 2 rs4880, and glutathione peroxidase 1 rs1050450 gene polymorphisms in a Turkish population. Methods: The study group included 121 unrelated keratoconus patients and 94 unrelated healthy controls. Blood samples (200 ml) were collected from all patients and controls to isolate genomic DNA. Genotyping was performed to identify rs1001179, rs4880, and rs1050450 using real-time polymerase chain reaction (PCR). Genotype and allele frequencies were calculated; their associations with keratoconus risk were assayed, and the association with keratoconus risk and demographic factors was examined. Results: Glutathione peroxidase 1 rs1050450 polymorphism was present in 41% cases compared with 29% controls (OR=1.66; 95% CI=1.11-2.50; p=0.014). No association was observed between catalase rs1001179 and SOD2 rs4880 polymorphisms and keratoconus (for all, p>0.05). Conclusions: This study evaluated possible relationships between rs1050450, rs1001179, and rs4880 polymorphisms and keratoconus susceptibility. We found a possible association between glutathione peroxidase 1 rs1050450 polymorphism and an increased risk of keratoconus. However, the genotype and allele frequencies were identical in the catalase rs1001179 and superoxide dismutase 2 rs4880 polymorphisms. Further studies are needed to analyze the effect of such variations in identifying keratoconus susceptibility.

RESUMO Objetivo: Investigar as possíveis associações entre o ceratocone e os polimorfismos rs1001179 da catalase, rs4880 da superóxido-dismutase 2 e rs1050450 da glutationa-peroxidase 1 rs1050450 em uma população turca. Métodos: O grupo de estudo incluiu 121 pacientes com ceratocone não relacionados e 94 controles saudáveis também sem pa rentesco. Amostra de sangue (200 mL) foram coletadas de todos os pacientes e controle para isolar o DNA genômico. A genotipagem foi realizada para identificar rs1001179, rs4880 e rs1050450 utilizando a reação em cadeia da polimerase (PCR) em tempo real. As frequências de genótipos e alelos foram calculadas, suas associações com o risco de ceratocone foram avaliadas, e a associação com risco de ceratocone e fatores demográficos foi examinada. Resultados: O polimorfismo da glutationa-peroxidase 1 rs1050450 estava presente em 41% dos casos, comparado com 29% dos controles (OR=1,66, IC 95%=1,11-2,50; p=0,014). Não foi observada associação entre o ceratocone e os polimorfismos rs1001179 e SOD2 rs4880 da catalase (para todos, p>0,05). Conclusões: Este estudo avaliou possíveis relações entre os polimorfismos rs1001179, rs4880 e suscetibilidade a cerato cone. Encontramos uma possível associação entre po limorfis mo da glutationa-peroxidase 1 rs1050450 e um risco aumentado de ceratocone. No entanto, o genótipo e as frequências alélicas foram idênticas nos polimorfismos rs1001179 da catalase e superóxido-dismutase 2 rs4880. Mais estudos são necessários para esclarecer o efeito dessas va riações na detecção da sus cetibilidade ao ceratocone.

Color vision versus pattern visual evoked potentials in the assessment of subclinical optic pathway involvement in multiple sclerosis.

Background: Optic pathway involvement in multiple sclerosis is frequently the initial sign in the disease process. In most clinical applications, pattern visual evoked potential (PVEP) is used in the assessment of optic pathway involvement. Objective: To question the value of PVEP against color vision assessment in the diagnosis of subclinical optic pathway involvement. Materials and Methods: This prospective, cross-sectional study included 20 multiple sclerosis patients without a history of optic neuritis, and 20 healthy control subjects. Farnsworth-Munsell (FM) 100-Hue testing and PVEPs to 60-min arc and 15-min arc checks by using Roland-Consult RetiScan® system were performed. P100 amplitude, P100 latency in PVEP and total error scores (TES) in FM 100-Hue test were assessed. Results: Expanded Disability Status Scale score and the time from diagnosis were 2.21 ± 2.53 (ranging from 0 to 7) and 4.1 ± 4.4 years. MS group showed significantly delayed P100 latency for both checks (P < 0.001). Similarly, MS patients had significantly increased total error scores (TES) in FM-100 Hue (P < 0.001). The correlations between TESs and PVEP amplitudes / latencies were insignificant for both checks (P > 0.05 for all). 14 MS patients (70%) had an increased TESs in FM-100 Hue, 11 (55%) MS patients had delayed P100 latency and 9 (45%) had reduced P100 amplitude. The areas under the ROC curves were 0.944 for FM-100 Hue test, 0.753 for P100 latency, and 0.173 for P100 amplitude. Conclusions: Color vision testing seems to be more sensitive than PVEP in detecting subclinical visual pathway involvement in MS.