Effects of race/ethnicity on triple CGG counts in the FMR1 gene in infertile women and egg donors

This cross-sectional cohort study investigated 385 females (344 infertile women and 41 oocyte donors), the numbers of CGG repeats on the FMR1 gene and differences between races/ethnicities. Traditional definitions of neuropsychiatric risks are classified as common, intermediate, premutation and full mutation ranges. Normal CGG count range was here, however, defined by box and whisker plot as 26–32 repeats (median 30). Distribution of abnormal outliers in CGG counts from this normal range was then compared between women of Caucasian, African and Asian descent. African and Asian women demonstrated a higher prevalence of two normal count alleles (65%) than Caucasians (54.3%; P = 0.03). Caucasians demonstrated the highest rate of allele abnormalities (43.3%) and were the only race/ethnicity also demonstrating abnormalities in both FMR1 alleles. Asian women demonstrated significantly fewer low outlier counts than Caucasians (P = 0.002) and Africans (P = 0.03). This study, thus, suggests significant racial/ethnic differences in triple CGG counts on the FMR1 gene between races/ethnicities. Since CGG counts on FMR1 are associated with ovarian reserve, these findings may reflect potential differences between races/ethnicities in ovarian function and female fertility reported in the literature.