P1811GENETIC POLYMORPHISMS IN STAT4, VEGF2578 AND PTPN22 GENES IN CHILDREN WITH GLOMERULOPATHIES
Authors: Kazyra Ina , Sukala Alexandr , Bialkevich Hanna , Krylova-Alefirenko Anna , Tur Natalia , Shynkarenka Yulia , Goncharova Roza , Nikitchenko Natallia , Siniauskaya Elisaveta , Savina Nataliya 
Published: June 2020

Abstract

Background and Aims
Glomerular diseases (GD) often have genetic predisposition, especially those autoimmune or immune complex-mediated. Our aim was to assess an impact of genetic polymorphism in STAT4 rs7574865 and rs3821236, VEGF rs699947 and PTPN22 rs2476601 on the risk of development of primary (PG) and secondary (SG) glomerulopathies in children.

Method
We enrolled 81 child with GD (m:f 33/48) and 335 healthy controls (m:f 184/151). Patients of the study group were arranged into two groups: 1st - with PG (38 children aged 3-17 yrs, 13±3,45, m:f 22/16) and 2nd - with SG (43 children aged 7-17 yrs, 13±3,59, m:f 11/32).
1st group included 35 patients with hereditary nephritis, 2 with IgA nephropathy, 1 – FSGS. 2nd group included 10 patients with ANCA associated vasculitis, 11 with IgA vasculitis, 22 with systemic lupus erythematosus (SLE). These patients were identified and monitored at the National Center for Pediatric Nephrology. Control group (CG) was matched with the study groups for age and sex and included 335 healthy children (m:f 184/151, age 2-17 yrs, 14,28±2,56). We analyzed DNA by polymerase chain reaction for identification of genotypes.

Results
The frequency of genotypes and allels for STAT4 rs 7574865 was found to be GG 55,26% in 1st, 46,51% in 2nd versus (vs) 62,09% in CG; GT 39,47%, 41,86% vs 32,24%; TT 5,26%, 11,63% vs 5,67%; for minor allele T 25,00%, 32,60% vs 21,79%, respectively. For STAT4 rs3821236: GG found in 65,79% in 1st, 55,81% in 2nd vs 65,07% in CG; GA genotype in 26,32%, 41,86% and 30,15%; AA genotype in 7,89%, 2,33% and 4,78%; minor allele A in 21,05%, 23,26% and 19,85%, respectively. For VEGF2578 rs 699947: AA 28,95% in 1st, 30,23% in 2nd vs 20,30% in CG; AC 44,74% and 51,16% vs 57,31%; CC 26,32% and 18,60% vs 22,39%; minor allele C 48,68%, 44,19% vs 51,04% in 1st and 2nd vs CG, respectively. For PTPN22: CC 68,42% in 1st, 59,46% in 2nd vs 72,95% in CG; CT 28,95%, 35,14%, 24,59%; TT 2,63%, 5,41% and 2,46%; minor allele T in 17,11%, 22,97% vs 14,75% in 1st,2nd and CG, respectively.
The distribution of genotypes observed was tested with the Hardy-Weinberg Equilibrium. There were no differences found in rates of polymorphic genotypes in CG and patients with GD.
For PTPN22 rs 2476601 and VEGF2578 rs6999467 no statistically significant difference between children of 1st, 2nd and CG was observed. We found the difference between patients with GD and healthy children (HC) for minor allele T of STAT4 rs7574865 (OR [95%CI]=1,73 [1,06-2,82], p=0,03), which was most prominent for female patients with SG (OR [95%CI]=2,31 [1,3-4,12], p=0,005). The development of SG was associated with the presence of GT+TT genotype (vs GG genotype) of STAT4 rs7574865 (OR=4,92; 95% CI [2,62-9,23]; p&lt;0,001).
Statistical testing showed significant differences between healthy female controls and SLE females for minor allele T of STAT4 rs7574865 (OR [95%CI]=2,14 [1,07-4,27], p=0,04) and GT+TT genotypes vs GG genotype of STAT4 rs7574865 (OR=2,54; 95%CI[1,00-6,42]; p&lt;0,05).
The analysis of genotypes/alleles for polymorphic locus rs3821236 of STAT4 revealed significant association of GA genotype (OR[95%CI]=2,55 [1,17-5,55], p=0,021), as well as of the sum of genotypes with at least one minor allele (GA+AA) (OR[95%CI]=3,51 [1,59-7,76], p=0,002) with the development of SG in girls. An association of the presence of the minor allele A of STAT4 rs3822136 with the likelihood of SG development in females was observed (OR[95%CI]=2,69 [1,5-4,83], p=0,001).

Conclusion
Minor allele T and GT+TT genotypes of STAT4 rs7574865 is associated with the risk of SG development in children and especially with the risk of SLE development in girls. Minor allele A and GA+AA genotypes of the STAT4 rs3822136 are associated with the predisposition to SG in girls. Minor allele T and GT+TT genotypes of the PTPN22 rs 2476601 are observed to be more frequent in both groups of GD and especially in girls, though failed to be statistically significant (p&gt;0,05).