Typing of C1q rs292001 polymorphism using restriction fragment length polymorphism and measuring serum levels of C1q protein and antibodies by enzyme-linked immunosorbent assay (ELISA) were performed for 130 children with SLE and 208 healthy controls.
We investigated whether a single nucleotide polymorphism (SNP) of the STAT4 (rs7574865), PTPN22 (rs2476601), TRAF1/C5 (rs10818488), and C1q (rs292001) genes as well as the 27-bp VNTR polymorphism on intron 4 of eNOS, previously associated with SLE in other populations, are also associated with SLE risk in Turkey.
We demonstrated 2 novel and 3 previously reported variants in genes associated with SLE: a homozygous non-sense alteration (c.622C>T/p.Gln208Ter) in <i>C1QA</i> in 2 patients; homozygous non-sense alteration (c.79C>T/p.Gln27Ter) in <i>C1QC</i> in 1 (novel variant); homozygous missense alteration (c.100G>A/p.Gly34Arg) in <i>C1QC</i> in 1; homozygous missense alteration (c.1945G>C/p.Ala649Pro) in <i>C1S</i> in 1 (novel variant); and homozygous frameshift alteration (c.289_290delAC/p.Thr97Ilefs*2) in <i>DNASE1L3</i> in 1 patient.
The identification of new mutation in C1qA gene that disrupts the start codon (ATG to AGG (Met1Arg)) has not been reported previously and it expands the knowledge and importance of the C1q gene in the pathogenesis of lupus especially in the high-risk African-American population.