ABCB1 gene variants as risk factors and modulators of age of onset of demyelinating disease in Mexican patients.

INTRODUCTION: The C1236T, G2677T/A, and C3435T variants of the ABCB1 gene alter the functioning of P-glycoprotein and the transport of endogenous and exogenous substances across the blood-brain barrier, and act as risk factors for some neurodegenerative diseases. This study aimed to determine the association between demyelinating disease and the C1236T, G2677T/A, and C3435T variants of ABCB1 and its haplotypes and combinations of genotypes. METHODS: Polymerase chain reaction with restriction fragment length polymorphism analysis (PCR-RFLP) and Sanger sequencing were used to genotype 199 patients with demyelinating disease and 200 controls, all Mexicans of mixed race; frequencies of alleles, genotypes, haplotypes, and genotype combinations were compared between patients and controls. We conducted a logistic regression analysis and calculated chi-square values and 95% confidence intervals (CI); odds ratios (OR) were calculated to evaluate the association with demyelinating disease. RESULTS: The TTT and CGC haplotypes were most frequent in both patients and controls. The G2677 allele was associated with demyelinating disease (OR: 1.79; 95% CI, 1.12-2.86; P =  .015), as were the genotypes GG2677 (OR: 2.72; 95% CI, 1.11-6.68; P =  .025) and CC3435 (OR: 1.82; 95% CI, 1.15-2.90; P =  .010), the combination GG2677/CC3435 (OR: 2.02; 95% CI, 1.17-3.48; P =  .010), and the CAT haplotype (OR: 0.21; 95% CI, 0.05-0.66; P =  .001). TTTTTT carriers presented the earliest age of onset (23.0 ±â€¯7.7 years, vs 31.6 ±â€¯10.7; P =  .0001). CONCLUSIONS: The GG2677/CC3435 genotype combination is associated with demyelinating disease in this sample, particularly among men, who may present toxic accumulation of P-glycoprotein substrates. In our study, the G2677 allele of ABCB1 may differentially modulate age of onset of demyelinating disease in men and women.

Perceived discrimination in patients with multiple sclerosis and depressive symptomatology.

BACKGROUND: Multiple Sclerosis is the central nervous system's most common demyelinating disease and the second leading cause of neurological disability in young adults. Its natural development involves physical and cognitive impairment. Patients commonly perceive discrimination against them, regardless of its occurrence, accepting it as an inherent part of the disease. OBJECTIVE: This study aimed to determine the association between perceived discrimination and the depressive symptoms and physical disability present in patients diagnosed with multiple sclerosis, treated at the Demyelinating Diseases Clinic of the National Institute of Neurology and Neurosurgery, Manuel Velasco Suárez. METHODS: A cross-sectional study was conducted in 98 patients diagnosed with multiple sclerosis. Demographic and clinical variables were obtained through clinical interviews. The severity of the disease was determined using the Extended Disability Status Scale (EDSS), depressive symptoms were assessed with the Beck Depression Inventory (BDI), and perceived discrimination was rated using the King Internalized Stigma Scale. RESULTS: The studied sample's mean age was 36.3 years, schooling 13.6 years, symptoms onset was at 26.2 years (with a delay in diagnosis of 3.2 years), and a disease evolution of 10.9 years. 71.4% were single; 52% had an unpaid work activity and 57.1% were women. The EDSS average was 3.5 points; 24.5% presented moderate to severe depressive symptoms and 53.1% referred perceived discrimination. CONCLUSIONS: Perceived discrimination in patients with multiple sclerosis was associated with earlier disease onset, depressive symptoms, and the lack of caregivers. Medical care and life quality improvement for this vulnerable group require greater education regarding the disease and the establishment of patient support programs.

ABCB1 gene variants as risk factors and modulators of age of onset of demyelinating disease in Mexican patients. / Variantes del gen ABCB1 como factores de riesgo y factores moduladores de la edad de inicio en pacientes mexicanos con enfermedad desmielinizante.

INTRODUCTION: The C1236T, G2677T/A, and C3435T variants of the ABCB1 gene alter the functioning of P-glycoprotein and the transport of endogenous and exogenous substances across the blood-brain barrier, and act as risk factors for some neurodegenerative diseases. This study aimed to determine the association between demyelinating disease and the C1236T, G2677T/A, and C3435T variants of ABCB1 and its haplotypes and combinations of genotypes. METHODS: Polymerase chain reaction with restriction fragment length polymorphism analysis (PCR-RFLP) and Sanger sequencing were used to genotype 199 patients with demyelinating disease and 200 controls, all Mexicans of mixed race; frequencies of alleles, genotypes, haplotypes, and genotype combinations were compared between patients and controls. We conducted a logistic regression analysis and calculated chi-square values and 95% confidence intervals (CI); odds ratios (OR) were calculated to evaluate the association with demyelinating disease. RESULTS: The TTT and CGC haplotypes were most frequent in both patients and controls. The G2677 allele was associated with demyelinating disease (OR: 1.79; 95% CI: 1.12-2.86; P=.015), as were the genotypes GG2677 (OR: 2.72; 95% CI: 1.11-6.68; P=.025) and CC3435 (OR: 1.82; 95% CI: 1.15-2.90; P=.010), the combination GG2677/CC3435 (OR: 2.02; 95% CI, 1.17-3.48; P=.010), and the CAT haplotype (OR: 0.21; 95% CI: 0.05-0.66; P=.001). TTTTTT carriers presented the earliest age of onset (23.0±7.7 years, vs. 31.6±10.7; P=.0001). CONCLUSIONS: The GG2677/CC3435 genotype combination is associated with demyelinating disease in this sample, particularly among men, who may present toxic accumulation of P-glycoprotein substrates. In our study, the G2677 allele of ABCB1 may differentially modulate age of onset of demyelinating disease in men and women.

Variantes del gen ABCB1 como factores de riesgo y factores moduladores de la edad de inicio en pacientes mexicanos con enfermedad desmielinizante / ABCB1 gene variants as risk factors and modulators of age of onset of demyelinating disease in Mexican patients

Introducción: Las variantes C1236T, G2677T/A y C3435T del gen ABCB1 alteran la función de la glicoproteína P y el transporte de sustancias endógenas y exógenas en la barrera hematoencefálica; además, actúan como factores de susceptibilidad para algunas enfermedades neurodegenerativas.El objetivo del estudio fue determinar la asociación de polimorfismos ABCB1 (C1236T, G2677T/A y C3435T), sus haplotipos y sus combinaciones de genotipos con la enfermedad desmielinizante.MétodoSe genotipificó a 199 pacientes con enfermedad desmielinizante y a 200 controles mestizos mexicanos mediante PCR-RFLP y secuenciación Sanger para comparar las frecuencias de alelos, genotipos, haplotipos y combinaciones de genotipos entre pacientes y controles. El análisis estadístico se realizó con regresión logística y χ2 de Pearson al 95% de confianza; se calculó la OR y se evaluó la asociación con enfermedad desmielinizante.ResultadosLos haplotipos TTT y CGC fueron los más frecuentes en pacientes y controles. El alelo G2677 (OR = 1,79; IC 95%: 1,12-2,86; p = 0,015) muestra asociación con enfermedad desmielinizante, así como los genotipos GG2677 (OR = 2,72; IC 95% = 1,11-6,68; p = 0,025) y CC3435 (OR = 1,82; IC 95%: 1,15-2,90; p = 0,010) y su combinación GG2677/CC3435 (OR = 2,02; IC 95%: 1,17-3,48; p = 0,010) y el haplotipo CAT (OR = 0,21; IC 95%: 0,05-0,66; p = 0,001).Los portadores TTTTTT presentaron la edad de inicio más temprana (23,0 ± 7,7 vs. 31,6 ± 10,7; p = 0,0001).ConclusionesLa combinación de genotipos GG2677/CC3435 está asociada al desarrollo de enfermedad desmielinizante en esta muestra, principalmente en el sexo masculino, en el cual puede darse acumulación tóxica de sustratos de glicoproteína P.En este estudio, la edad de inicio de la enfermedad desmielinizante podría ser modulada diferencialmente entre sexos por el alelo G2677 del gen ABCB1. (AU)

Introduction: The C1236T, G2677T/A, and C3435T variants of the ABCB1 gene alter the functioning of P-glycoprotein and the transport of endogenous and exogenous substances across the blood-brain barrier, and act as risk factors for some neurodegenerative diseases.This study aimed to determine the association between demyelinating disease and the C1236T, G2677T/A, and C3435T variants of ABCB1 and its haplotypes and combinations of genotypes.MethodsPolymerase chain reaction with restriction fragment length polymorphism analysis (PCR-RFLP) and Sanger sequencing were used to genotype 199 patients with demyelinating disease and 200 controls, all Mexicans of mixed race; frequencies of alleles, genotypes, haplotypes, and genotype combinations were compared between patients and controls. We conducted a logistic regression analysis and calculated chi-square values and 95% confidence intervals (CI); odds ratios (OR) were calculated to evaluate the association with demyelinating disease.ResultsThe TTT and CGC haplotypes were most frequent in both patients and controls. The G2677 allele was associated with demyelinating disease (OR: 1.79; 95% CI: 1.12-2.86; P = .015), as were the genotypes GG2677 (OR: 2.72; 95% CI: 1.11-6.68; P = .025) and CC3435 (OR: 1.82; 95% CI: 1.15-2.90; P = .010), the combination GG2677/CC3435 (OR: 2.02; 95% CI, 1.17-3.48; P = .010), and the CAT haplotype (OR: 0.21; 95% CI: 0.05-0.66; P = .001).TTTTTT carriers presented the earliest age of onset (23.0 ± 7.7 years, vs. 31.6 ± 10.7; P = .0001).ConclusionsThe GG2677/CC3435 genotype combination is associated with demyelinating disease in this sample, particularly among men, who may present toxic accumulation of P-glycoprotein substrates.In our study, the G2677 allele of ABCB1 may differentially modulate age of onset of demyelinating disease in men and women. (AU)