Variable expression of the Fragile X Mental Retardation 1 (FMR1) gene in patients with premature ovarian failure syndrome is not dependent on number of (CGG)n triplets in exon 1

BACKGROUND: Increased expression of the Fragile X Mental Retardation I (FMRI) gene in blood cells has been claimed to be associated with variable (CGG) n triplet numbers in the 5' untranslated region of this gene. Increased CGG triplet numbers, including that of the so-called premutation range (n = 55-200), were shown to have a risk of 90). During normal folliculogenesis, FMRP is predominantly expressed in granulosa cells. CONCLUSIONS: Our data suggest that FMRI expression during human folliculogenesis is probably a quantitative trait. Proper function of FMRP in granulosa cells seems to depend on an optimal transcript level. All women with CGG triplet numbers outside the range associated with normal folliculogenesis (26 34) are therefore expected to have a relaxed FMRI transcription control. FMRI transcript levels in leukocytes might therefore be diagnostic for altered FMRP levels in granulosa cells, which will affect the process of folliculogenesis.