ABSTRACT
Objective To explore the associations between vitamin D receptor ( VDR) Fok- Ⅰ and Apa- Ⅰ polymorphisms and myasthenia gravis (MG) in Chinese Han population.Methods Polymorphisms of VDR Fok- Ⅰ and Apa-Ⅰ were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.The frequencies of genotypes and hyplotypes were compared among 286 normal controls and 267 MG patients in different subgroups classified by gender,age of onset,presence of thymoma,and Osserman classification sat maximal severity in the follow-up.The association between the genotypes and maximal severity of MG and short-term glucocorticoid treatment were also investigated.Results There were no significant differences in frequencies of genotypes and hyplotypes of both Fok-Ⅰ and Apa-Ⅰ between MG group and control group,and among subgroups of MG.The Fok- Ⅰ showed no statistical difference between the patients with better and less improvement after short-term treatment of glucocorticoid.The frequency of Apa-Ⅰ alleles in the patients with better improvement (55/186,29.6% ) significantly differed from the less improved group ( 7/48,14.6%,OR = 2.46,95% CI 1.04-10.43,x2 = 4.400,P = 0.036).The patients with the genotype A A/Aa were more likely to improve better after the treatment(48/93,51.6%) than in the worse group(7/24,29.2%,OR =2.59,95% CI 0.98-14.60,x2 =3.858,P= 0.049).Conclusions Alleles and genotypes of VDR-Fok- Ⅰ and Apa-Ⅰ were not found to be related with MG onset and severity.MG patients with VDR-Apa-A allele may have better improvement short-term treatment of glucocorticoid.