UK Edition
Women's genes change during PMT, scientists find, raising hope for cure
A treatment for pre-menstrual tension (PMT) could be on the horizon after scientists found that genes go haywire as hormones change during a woman’s monthly cycle.
Up to 80 per cent of women complain of irritability, depression and anxiety in the days leading up to their period but it was widely believed to be a mood disorder triggered by fluctuations in chemicals in the brain.
For around one in 20, the condition is so severe that they need anti-depressants and can suffer disabling headaches, severe fatigue and aching muscles.
Now scientists have discovered that in women who suffer PMT (also called premenstrual syndrome or PMS) the change in hormones before their period radically alters how their genes function. Some genes, which should become active actually dial back, while others which should be quiet become more energetic.
Researchers from the National Institutes for Health (NIH), in the US, described the finding as a significant breakthrough because it proves for the first time that women are not simply suffering mood swings. In fact, their whole biology is out of joint.
"This is a big moment for women's health, because it establishes that women have an intrinsic difference in their molecular apparatus for response to sex hormones - not just emotional behaviors they should be able to voluntarily control," said Dr David Goldman, of the NIH.
Researchers believe that women who suffer from severe PMT are genetically much more sensitive to surges of hormones, which occur throughout the menstrual cycle.
To test whether the sensitivity was having an impact on cells, the team looked a white blood cells from women with severe PMT and compared them to the cells of women who never suffer symptoms.
White blood cells express many of the same genes as brain cells, so studying them can give a window into what is happening in the brain.
Scientists found a particular circuit of genes - known as the ESC/E(Z) complex - behaved oddly when exposed to increases in oestrogen. While the sex hormone boosted activity in the genes of women who did not suffer PMT, it had the opposite impact on those who got severe symptoms.
Dr Peter Schmidt, of the NIH’s National Institute of Mental Health, added: “We found dysregulated expression in a suspect gene complex which adds evidence that (severe pre-menstrual tension) is a disorder of cellular response to oestrogen and progesterone.
"Learning more about the role of this gene complex holds hope for improved treatment of such prevalent reproductive endocrine-related mood disorders."
For the first time, we now have cellular evidence of abnormal signaling in cells derived from women with [severe PMT], and a plausible biological cause for their abnormal behavioral sensitivity to oestrogen and progesterone."
The researchers are now following up the discovery in the hopes of gaining more information about how hormones alter neurons.
In 2014 a study by Bristol University and University College London found that women are effectively going through drug withdrawal in the days before their period, triggered by low levels of the hormone progesterone.
When progesterone breaks down in the body it produces a chemical called allopregnanolone which acts on the brain as a powerful sedative and tranquiliser. When the brain is deprived of those calming chemicals it can cause low mood, they suggested.
However the study was only carried out on rats.