Table 1.

Characteristics of the studied genetic polymorphisms.

Gene	Polymorphism and base change	Comments
TGFB1 Transforming growth factor beta 1	rs1800469 (T/C)	Polymorphism rs1800469 is located in the promoter region of the TGFB1 gene and has the function of regulating expression levels of protein TGFβ1 (affects gene transcriptional activity and serum levels of TGFβ1) [19, 20].
	rs4803455 (C/A)	The polymorphism rs4803455 is located in intron 2 of TGFB1 gene and was associated with a variety of different conditions (https://www.ncbi.nlm.nih.gov/snp/rs4803455). Moreover, it was suggested as a potential genetic marker for growth response to recombinant human growth hormone (r-hGH) treatment [38].
TGFBR2 Transforming growth factor beta receptor 2	rs3087465(A/G)	Polymorphism rs3087465 is located in the promoter region of the gene and increases TGFβ type II receptor expression [26].
	rs764522 (G/C)	The polymorphism rs764522, which is located in 5 kb upstream in the promoter region of TGFBR2 increases TGFβ type II receptor expression [26].