In SLE, primary study, performed by Tanev et al., has demonstrated no significant differences in allelic and genotype distribution of MTNR1b gene (rs1562444, rs10830962, and rs10830963) polymorphisms between 109 patients with SLE and 101 controls, yet, in SLE patients, C/C genotype of rs10830963 in MTNR1b gene was related to increased prevalence of leucopenia compared to C/G and G/G genotype; the rs10830963 G/G carriers had a lower number of lupus criteria than in those with C/C genotype [25]. The gene discussed is MTNR1B; the disease is systemic lupus erythematosus.