The effect of galanin gene polymorphism rs948854 on the severity of multiple sclerosis: A significant association with the age of onset

Association between MEF2 family gene polymorphisms and susceptibility to multiple sclerosis in Chinese population

PURPOSE

Multiple sclerosis (MS) is an autoimmune disease characterized by inflammatory demyelinating lesions in the white matter of the central nervous system. Myocyte enhancer factor 2 (MEF2) family genes play important roles in the immune response. This study focuses on the relationship between MEF2 family gene polymorphisms and MS.

METHODS

A total of 174 MS patients and 120 healthy controls were recruited. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to analyze the gene polymorphisms of MEF2D and MEF2C. In addition, peripheral blood was collected and leukocytes were isolated. The transcription level of MEF2D in the two groups of samples was detected with quantitative real time polymerase chain reaction (qRT-PCR).

RESULTS

We found that the C allele frequency and CC genotype frequency of rs2274316 in MEF2D were significantly higher in MS patients. The C allele and CT genotype distribution for rs3790455 were significantly more frequent in MS patients. Female patients showed higher CC genotype frequency of rs2274316. The genotype frequency distribution of rs2274316 and rs3790455 were not related to onset age and phenotype of MS patients. In addition, this study also proved that MEF2D was significantly overexpressed in the peripheral blood leukocytes of MS patients. The transcription level of MEF2D was significantly higher in patients with CC genotype of rs2274316.

CONCLUSION

These findings suggest rs2274316 and rs3790455 of MEF2D gene are potential genetic risk factors for MS in Chinese population. The transcription level of MEF2D is also associated with susceptibility to MS and MEF2D gene polymorphisms.

A common genetic variant rs2821557 in KCNA3 is linked to the severity of multiple sclerosis

The rate of symptom accumulation distinguishes between slowly and rapidly progressing forms of multiple sclerosis (MS). Given that a patient's genetics can affect the rate of disease progression, identification of genetic variants associated with rapid disease progression should provide valuable information for timely prognosis and development of optimal treatment plans. We hypothesized that the polymorphism rs2821557 in the human KCNA3 gene encoding a voltage-gated potassium channel Kv1.3 might be one of these genetic variants, given the role of Kv1.3 in neuroinflammation, as well as the location and gain-of-function effect of this polymorphism. To test this hypothesis we performed an analytic study exploring the relationships between rs2821557 polymorphism and disease progression in a cohort of MS patients. The rs2821557 genotype and the rate of disease progression based on Multiple Sclerosis Severity Score (MSSS) were determined for 101 patients (68 females and 33 males). Peripheral blood CD4+ lymphocyte subpopulations (T_naive , T_CM , T_EM ) and the expression of chemokine receptors (CXCR5, CXCR3, CCR6, CCR4) were estimated by flow cytometry. The comparisons between groups by genotype (TT, TC, CC) and allelic approach analysis (T vs. C) revealed a significantly higher incidence of the rapid disease course (MSSS ≥ 7.5) among minor C allele carriers (CC and TC) compared to patients with the TT genotype. Furthermore, C allele carriers had higher counts of CXCR3+ T_EM cells than homozygous T allele carriers. In conclusion, accelerated MS progression in C allele carriers is likely linked to enhanced Kv1.3-mediated accumulation of pathogenic CXCR3+ T_EM cells and exacerbated neuroinflammation.