Endocrine Abstracts

Gynecomastia is a benign enlargement of the male breast due to the imbalance between androgens and estrogens in the breast tissue. In up to 40% of cases no evident reasons could be found. This idiopathic gynecomastia may be caused by excess aromatisation within breast tissue. Aromatase is a key enzyme in estrogen biosynthesis. Mutations and polymorphisms of aromatase gene could lead to its overexpression. Some endocrine disruptors - chemicals that interfere with hormone function, could induce aromatase activity. Action of the environmental pollutants in individuals with polymorphism might be a cause of idiopathic gynecomastia.

The aim is to evaluate the association between a (TTTA)n repeat polymorphism in intron 4 of aromatase gene and gynecomastia.

DNA was extracted from the blood taken from 30 patients with gynecomastia and 8 men from control group. The specific primers marked with FAM fluorescent stain were added and the region of the CYP19 gene containing the polymorphic TTTA repeats at 174 bp was amplified by PCR. The products were electrophoresed in polyacrylamide gel to verify the PCR reaction and sequenced using the ABI3100 to examine the length of the products.

We found 5 different allels (TTTA)n (n=7,8,10,11,12) and 3 allels (TTTA)n - 3 bp with a 3 bp deletion just 50 bp upstream of the tetranucleotide repeat sequence. Allels (TTTA)11 were more frequent in men with idiopathic gynecomastia than in gynecomastia of other reasons and in control group (25,7%; 19,2% and 12,5% respectively) and (TTTA)7 – 3 bp were more infrequent (14%, 26,9% and 25% respectively). In few men we observed 3 or 4 products amplified by PCR and we are investigating the reason of that findings now.

This preliminary report indicate the possible importance of (TTTA)n repeat aromatase gene polymorphism in gynecomastia. We are evaluating this association by examining more samplings.