Without Bonferroni correction we observed that: a) in dominant model in MECP2 rs1734787 C/A median age of SLE patients, which is 30.5 years in CC+CA genotype and 39 years in AA genotype is statistically significant (p = 0.02), b) patients with allele A have statistically significant (p = 0.04) much more value of ESR, which is 13.5 mm/h than those with allele C with ESR of 0.7 mm/h, c) however, patients with allele C in comparison with allele A have much more level of creatinine (28 vs. 0.98 mg/dL, p = 0.01), ALT (38 vs. 20 U/L, p = 0.04) and AST (38.62 vs. 23.17 U/L; p = 0.01). The gene discussed is MECP2; the disease is systemic lupus erythematosus.