Sydney: Alteration of a single gene could turn some male embryos into female ones, according to a study that may help treat males who develop feminine appearance.
The study will improve diagnosis and clinical management of patients with disorders of sex development (DSD).
These disorders occur when the testis or ovary does not develop properly in the embryo, causing genital abnormalities in one out of 4,500 babies, reports the American Journal of Human Genetics.
An international team, including University of Melbourne researchers, identified the gene alteration in a group of patients that included two families with several affected members.
The alteration occurred in a gene called MAP3K1, which plays a role in switching on genes that direct the gonad (a reproductive gland) to become a testis, according to a Melbourne statement.
Males normally have one X and one Y chromosome and females have two X chromosomes.
But researchers found that the alteration of the MAP3K1 gene disrupted the normal process of testis development, resulting in a male XY embryo developing female characteristics, including female genitalia and an overall feminine appearance.
Professor Andrew Sinclair, who led the Melbourne study, said the discovery showed the underlying cause of testis failure in these patients, which would help provide a diagnosis and guide clinical management of cases in the future.
"To date, we know of only a small number of genes that are involved in gonad development, and can only diagnose about 20 percent of DSD patients," he said.
"Based on our study, we believe mutation of the MAP3K1 gene could be responsible for a further 20 percent of XY DSD cases," said Sinclair.