Identification and validation of lncRNA mutation hotspot SNPs associated with myasthenia gravis susceptibility

Myasthenia gravis (MG) is an autoimmune disorder caused by antibodies that target the postsynaptic muscle membrane. Recent evidence suggests that genetic variants and long noncoding RNAs (lncRNAs) play crucial roles in the pathogenesis of MG. The purpose of this study was to investigate the associations between lncRNA-related single-nucleotide polymorphisms (SNPs) and MG susceptibility in Chinese populations.

First, we identified lncRNA mutation hotspot regions based on the improved Kolmogorov‒Smirnov test and the cumulative hypergeometric distribution principle. Next, we further identified lncRNA mutation hotspot SNPs by calculating conservative scores. Finally, experiments were conducted to verify the associations between lncRNA mutation hotspot SNPs and MG susceptibility. A total of 82 patients with MG and 82 healthy controls were recruited for genotyping of lncRNA mutation hotspot SNPs using the SNaPshot technique. Quantitative real-time PCR was used to investigate lncRNA expression in 34 patients with MG and 37 healthy controls.

In the multistep calculation, 14 candidate SNPs of 3 lncRNAs (AL031686.1, NONHSAT028539.2 and AC245014.3) in MG were identified as mutation hotspot SNPs. The genotyping results of the 14 SNPs in our study revealed no statistically significant differences in the frequencies of genotypes and alleles between patients with MG and controls. However, in the lncRNA AL031686.1, rs1000383 and rs6094353 were in perfect linkage disequilibrium (LD) and were associated with an increased risk of ocular MG. Additionally, rs6094347 was associated with an increased risk of ocular MG. Nevertheless, no SNP was found to be associated with factors such as sex, age, the presence or absence of thymoma, or the genetic model of MG. Further experiments revealed that NONHSAT028539.2 expression was upregulated in peripheral blood mononuclear cells (PBMCs) from patients with MG compared with those from healthy controls.

In our study, we did not find an association between the 14 mutation hotspot SNPs of lncRNAs and susceptibility to MG. However, we observed that the rs6094347 and rs1000383/rs6094353 polymorphisms in the lncRNA AL031686.1 were associated with the risk of ocular MG.