Functional Analyses of Endometriosis-Related Polymorphisms in the Estrogen Synthesis and Metabolism-Related Genes

Endometriosis is determined by genetic factors, and the prevalence of genetic polymorphisms varies greatly depending on the ethnic group studied. The objective of this study was to investigate the relationship between single nucleotide polymorphisms (SNPs) of 9 genes involved in estrogen biosynthesis and metabolism and the risks of endometriosis. Three hundred patients with endometriosis and 337 non-endometriotic controls were recruited. Thirty four non-synonymous SNPs, which change amino acid residues, were analyzed using matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS). The functions of SNP-resulted amino acid changes were analyzed using multiple web-accessible databases and phosphorylation predicting algorithms. Among the 34 NCBI-listed SNPs, 22 did not exhibit polymorphism in this study of more than 600 Taiwanese Chinese women. However, homozygous and heterozygous mutants of 4 SNPs - rs6165 (genotype GG+GA, 307^Ala/Ala+307^Ala/Thr) of FSHR, rs 6166 (genotype GG+GA, 680^Ser/Asn+680^Ser/Ser) of FSHR, rs2066479 (genotype AA+AG, 289^Ser/Ser+289^Ser/Gly) of HSD17B3 and rs700519 (genotype TT+TC, 264^Cys/Cys+264^Cys/Arg) of CYP19, alone or in combination, were significantly associated with decreased risks of endometriosis. Bioinformatics results identified 307^Thr of FSHR to be a site for O-linked glycosylation, 680^Ser of FSHR a phosphorylated site by protein kinase B, and 289^Ser of HSD17B3 a phosphorylated site by protein kinase B or ribosomal protein S6 kinase 1. Results of this study suggest that non-synonymous polymorphisms of FSHR, HSD17B3 and CYP19 genes may modulate the risk of endometriosis in Taiwanese Chinese women. Identification of the endometrosis-preferential non-synonymous SNPs and the conformational changes in those proteins may pave the way for the development of more disease-specific drugs.