Rs7537605 polymorphism in VAV3 gene and rs28665122 polymorphism in SEPS gene are not associated with Hashimoto's thyroiditis in North-East Algerian population

Background: Hashimoto's thyroiditis (HT) is the most common form of autoimmune thyroid disease which leads, in most cases, to hypothyroidism. HT is also classified as a multifactorial disease, which is caused by an interaction between genetic and environmental factors. Current knowledge of HT genetics is still very limited, especially in Algerian population. Objective: We wanted to investigate the association of two single-nucleotide polymorphisms (SNPs) inside VAV3 and SEPS genes with HT in Algerian population. Methods: We conducted a case-control study that included 100 HT cases and 126 healthy controls that were recruited from three private endocrinology clinics. Two SNPs, rs7537605 and rs28665122 inside VAV3 and SEPS genes were genotyped using real-time polymerase chain reaction (real-time PCR). Binary logistic regression model was used to test the association of selected SNs with HT and linear regression model was used to test association of these SNPs with thyroid peroxidase antibodies (TPOAb) levels. Results: Binary logistic regression results revealed no allelic association of the minor allele A between Hashimoto's thyroiditis cases and healthy controls (P=0.896) for the rs7537606 in VAV3 gene. The same observation was reported for the AA (P=0.477), AG (P=0.752) genotypes and for the genotypic models: dominant (P=1.0) and recessive (P=0.555). Also, there was no significant difference in the TT (P=0.230), TC (P=0.717) and allelic distribution of the minor allele T (P=0.859), and the combined models: TT + TC (P=1.0), TC + CC (P=0.138) between patients and controls for the rs28665122 polymorphism ofthe SEPS1 gene. Conclusion: This is the first genetic study that investigated the genetic association of rs7537605 and rs28665122 inside VAV3 and SEPS genes in Algerian population. Our results suggest that these two SNPs may not be involved in the pathogeneses of HT since we found no association between them and HT/TPOAb levels. Further research that will include larger sample size is required. Keywords: Hashimoto’s thyroiditis; inflammation; hypothyroidism; rs7537605; rs28665122; Algerian population.

Genotype association of IP6K3 gene with Hashimoto’s thyroiditis in Algerian population (Aures region)

Background

Hashimoto’s thyroiditis (HT) is a chronic autoimmune disease of the thyroid gland and is also the main cause of hypothyroidism. A recent genome-wide association study (GWAS) suggested an association of three novel genetic variants with HT in a population of Caucasian origin (Croatian). A case-control study was performed to investigate the association of these three newly suggested genetic variants with HT in a non-Caucasian ethnic group, an Arab-Berber from Algeria.

Three variants (rs12944194 located 206 kb from SDK2, rs791903 inside IP6K3, and rs75201096 inside GNA14) were genotyped using real-time PCR.

Results

There were no significant differences in allele frequencies of the three genetic variants between HT cases and controls. However, the present study showed nominal significance in the genotype distribution of rs791903 (IP6K3 gene) between HT patients and the control group (P = 0.024); we observed a decrease in the frequency of rs791903 recessive homozygotes (CC) in HT cases versus controls (OR = 0.476, P = 0.025).

Conclusion

This is the first study that showed the genotypic association of IP6K3 intronic variant with decreased risk for HT in non-Caucasian, Algerian, population, whereas we did not confirm the association of SDK2 and GNA14 genetic variants with HT. The IP6K3 gene (inositol hexaphosphate kinase 3), located near major histocompatibility complex (MHC), has previously been associated with other common autoimmune diseases beside HT, such as Graves’s disease and rheumatoid arthritis, which is providing more evidence of a good candidacy for the genetic contribution to the development of HT and autoimmunity.