Progesterone receptor gene alleles linked with endometriosis risk

January 2007

Women who carry the progesterone receptor (PR) gene allele +331A appear to have a reduced risk for deep infiltrating endometriosis compared with other women

K van Kaam and team from the University of Maastricht set out to determine the frequencies of progesterone receptor gene polymorphisms in women with deep infiltrating endometriosis because alterations in the progesterone receptor (PR) are considered a risk factor for the development of endometriosis.

The teamexamined the prevalence of the PR gene polymorphism +331G/A in women with deep infiltrating endometriosis (n = 72), adenomyosis in the uterine wall (n = 40), gynecological patients without symptomatic endometriosis (n = 102), and in healthy females (n = 93).

Results revealed that there was a significantly lower allelic frequency of the polymorphic allele +331A in women with endometriosis and in those with adenomyosis than in healthy females.

Furthermore, the expression levels of the PR-B isoform in enometriotic epithelium were significantly higher in women who carried the +331A allele (n=2) than in those who carried the +331G/G variant (n=61).

The researchers note, however, that as there were only two individuals with the +331A allele, it may not be possible to draw any definitive conclusions on the effect of this allele on the expression levels of PR-A and PR-B.

Van Kaam et al conclude that “the presence of the PR gene polymorphic allele +331A is associated with a reduced risk of deep infiltrating endometriosis and adenomyosis compared with healthy population controls. The PROGINS polymorphism does not seem to modify the risk of deep infiltrating endometriosis.”


van Kaam KJ, Romano A, Schouten JP, Dunselman GA, Groothuis PG. Progesterone receptor polymorphism +331G/A is associated with a decreased risk of deep infiltrating endometriosis. Human Reproduction 2007; 22: 129-35.

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