A gene variant that apparently causes female baldness has been discovered by researchers.
After studying the DNA of almost 500 women who had lost at least 50 per cent of the hair on top of their scalp, scientists from the University of Melbourne and St Vincent's Hospital made the discovery, reports The Age.
All the women in the study (between 18 and 65) suffered severe female pattern hair loss.
When compared with a control group who were not going bald, the women were all found to have a variant of the oestrogen receptor beta gene or ESR2, which seemed to make hair follicles more sensitive to the body's oestrogen levels.
The gene variant's link to hair loss was particularly strong in women over 40. Those who did not suffer baldness had a different variant of the same gene, which was less affected by oestrogen levels.
Rod Sinclair, professor of dermatology at St Vincent's and one of the trial's leaders, said: "Women often notice that their hair thickens up during pregnancy and they often experience hair loss after the delivery of the baby when they are breastfeeding, which is a low-oestrogen state, the same as the menopause stage."
Professor Sinclair said, "If you give a woman hormone replacement therapy there was the belief that the high oestrogen count might be good for the hair, but these findings suggest it's more likely to be the exact opposite. In situations where women are taking either the contraceptive pill or hormone replacement therapy and they experience hair loss it may be may advantageous to select low-oestrogen preparations to minimise the impact on hair."
The findings will be presented at the World Congress for Hair Research in Cairns next month.