RESEARCH FMR1-dependent variabilit e

Full list of author information is available at the end of the articleBackground The FMR1 gene, located on the X chromosome, is widely tested in prenatal medicine in attempts to prevent the so-called fragile X syndrome, representing the one-generational expansion of a premutation-range CGGn=55–200 to a full mutation, characterized by a CGGn>200. Based on a newly defined normal range of CGGn=26–34, it has only recently in a number of publications been associated with ovarian aging. Different mutations of the gene appear associated with different rates of follicle depletion. Lledo et al. recently, however, suggested that FMR1 screening should not be considered in pre-assessing po-tential responses to ovarian stimulation [1], implying that different FMR1 mutations do not correlate with variations in functional ovarian reserve (FOR). We, in contrast, pre-viously reported specific ovarian FMR1 genotypes and sub-genotypes, defined by normal range of CGGn=26–3