Abstract
A major component of the polycystic ovary syndrome (PCOS) is the insulin resistance.
Only a few studies have evaluated the IRS-1 polymorphism at codon 972, sometimes in
the absence of a control group, and with great variability in frequency (0–23% in
PCOS vs. 0–17% in controls), and with no unequivocal relationships between the polymorphism
and clinical or biochemical indexes. The aim of the work was to evaluate the frequency
of the IRS-1 polymorphism at codon 972 in PCOS, and correlate it to clinical and biochemical
indexes. We assessed the rs 1801278 polymorphic variant in the IRS-1 gene (Gly972Gly=wild-type;
Gly972Arg=heterozygosity; Arg972Arg=homozygosity) in genomic DNA by restriction fragment
length polymorphism. The study was conducted at an academic medical center with the
participation of 65 women with PCOS and 27 age-matched healthy women (controls). Compared
to controls, Gly972Arg was very frequent in PCOS (77% vs. 18%, p<0.0001); one PCOS
woman was homozygous. Compared to wild-type PCOS, heterozygous PCOS women had only
three significantly different indexes: higher fasting insulin, insulin resistance
index, and lower 120 min OGTT glucose. Moreover, in the correlation analysis between
any two clinical or biochemical variables, the Pearson's correlation coefficients
were frequently of different magnitude in heterozygous PCOS versus wild-type PCOS.
Overall, heterozygous PCOS had a greater number of statistically significant relationships
between different clinical, metabolic and hormonal indexes: 44 direct and 9 inverse
versus 6 and 3, respectively. The IRS-1 Gly972Arg has the highest frequency reported
world-wide for PCOS women. This variant is associated with insulin resistance and
higher fasting insulin in PCOS women.
Key words
insulin resistance - hyperandrogenism - single nucleotide polymorphisms
References
Correspondence
mapp20@libero.it
