Association of aromatase (TTTA)n repeat polymorphisms with central precocious puberty in girls.

Abstract

Objective: Precocious puberty is characterized by early activation of the pituitary gonadal axis. Estrogen is the final key factor to start onset of puberty. The cytochrome P450 19A1 (CYP19A1) gene encodes an aromatase that is responsible for the conversion of androgens to estrogen, which is key step in estrogen biosynthesis. The aim of this study is to identify CYP19A1 gene mutations or polymorphisms in girls with central precocious puberty (CPP).

Methods: We evaluated the frequency allelic variants of the CYP19A1 exons and the tetranucleotide tandem repeat (TTTA)n in intron 4 in 203 idiopathic central precocious puberty (CPP) girls and 101 normal healthy women.

Results: The genotype analysis of the CYP19A1 (TTTA)n polymorphism revealed six different alleles ranging from 7 to 13 repeats. Among the 6 different repeat allele detected in this study, (TTTA)13 repeat allele was only detected in patients group and the carriers of allele (TTTA)13 was significantly associated with a increased risk of CPP (OR=1.509, 95% CI=1.425-1.598, P=0.033). The carriers of the (TTTA)13 repeat allele were significantly younger age at pubertal onset and had higher levels of estrogen than non-carriers of (TTTA)13 repeat allele. Although nine polymorphisms were detected in exons of CYP19A1 gene, no clinical significance was observed.

Conclusion: In this study, the carriers of higher repeat (TTTA)13 polymorphism in intron 4 of the CYP19A1 gene had higher level of estrogen in this study. The carrying the (TTTA)13 repeat allele may have a higher risk of developing CPP.