[Study of the association of β2-adrenergic receptor gene polymorphism with Myasthenia Gravis associated with thymus abnormality].

OBJECTIVE

To investigate the association of two β2-adrenergic receptor (β2-AR) polymorphisms (Arg16Gly, Gln27Glu) with Myasthenia Gravis (MG) associated with thymus abnormality.

METHODS

Among the 74 MG patients in analysis, 24 cases were associated with thymoma, 40 cases with thymic hyperplasia, 12 with normal thymus. The genotypes of β2-AR in 76 MG (MGG) and 75 age and gender-matched healthy controls (HCG) were determined by polymerase chain reaction and nucleotide sequence determination.

RESULTS

The frequencies of three genotypes (Arg/Arg, Arg/Gly, Gly/Gly) and alleles (Arg, Gly) in position 16 between MGG with thymoma and HCG (genotype χ(2) = 0.460, P = 0.895; allele χ(2) = 0.137, P = 0.711), MGG with thymic hyperplasia and HCG were not statistically insignificant (genotype χ(2) = 2.585, P = 0.278;allele χ(2) = 0.300, P = 0.584). The difference in distribution of the genotypes (Gln/Gln, Gln/Glu, Glu/Glu) and alleles (Gln, Glu) between MGG with thymoma and HCG (genotype P = 0.866; allele χ(2) = 0.030, P = 0.860), MGG with thymic hyperplasia and HCG (genotype P = 0.907; allele χ(2) = 0.373, P = 0.542) were statistically insignificant. The genotypes distribution of position 27 in different thymus histology (thymoma, thymic hyperplasia, normal thymus) of MGG were significantly different (P = 0.041). The genotype frequencies in all groups were both in Hardy-Weinberg equilibrium (P > 0.05).

CONCLUSION

Arg/Gly and Gln/Glu polymorphisms of β2-AR might have no relationship with the risk of MG associated with thymus abnormality. The genotypes polymorphism of position 27 may related with the different thymus histology of MG.