New Genetic Test Predicts Better Egg Production for Women with Poor Ovarian Reserve, Study Shows

NEW YORK, NY, March 19, 2012 (Press-News.org) A genotype of the FMR1 (fragile X mental retardation) gene preserves a woman's ability to produce eggs (oocytes) well into the 40s, according to an ovarian aging study just published in the medical journal PLoS One1.

Conducted at the Center for Human Reproduction (CHR), a fertility center in New York City specializing in fertility treatments for older women, the study compared egg yields during in vitro fertilization (IVF) in women above age 40 with varying FMR1 genotypes and sub-genotypes.

In women with very poor ovarian reserve (i.e., women with the poorest ovarian function), the FMR1 sub-genotype het-norm/high (normal CGG repeat count on one allele, abnormally high count on the other) produced significantly more eggs than other genotypes and sub-genotypes. This observation suggests that the het-norm/high FMR1 sub-genotype preserves a woman's ability to produce a good number of eggs at older ages even if the ovarian reserve is severely reduced.

"From our previous research, we knew that the het-norm/high sub-genotype was responsible for slow recruitment of eggs into maturation process at younger ages than other genotypes and sub-genotypes," explains Norbert Gleicher, MD, lead author of the study and Medical Director of CHR. "Because these women 'use up' fewer eggs from their egg reserve, we suspected that they may have more eggs left when older. This study confirmed this hypothesis, demonstrating that women with this sub-genotype performed better in IVF cycles than even women with normal FMR1 genotype."

These findings further enhance the understanding of genetic control over the process of ovarian aging, and further refine prognostication in older women undergoing fertility treatments. Given that oocyte yields in IVF cycles usually correlate with pregnancy chances, older women with extremely low ovarian reserve, therefore, appear to have better chances of success if their FMR1 sub-genotype is het-norm/high.

1Gleicher N et al. The impact in older women of ovarian FMR1 genotypes and sub-genotypes on ovarian reserve. PLoS One 2012:e33638. [http://dx.plos.org/10.1371/journal.pone.0033638]

About Center for Human Reproduction
Center for Human Reproduction, or CHR (http://www.centerforhumanreprod.com), is a leading fertility center in the United States with a worldwide reputation as a "fertility center of last resort," specializing in treatment of infertility in women with diminished ovarian reserve, including younger women with premature ovarian aging (POA) and older women with physiological ovarian aging. Dr. Gleicher is available for additional comments.