Source of sex development disorders identified

Scientists have located the source of sex development disorders, which cause genital abnormalities in babies.

Washington: Scientists have located the "source" of sex development disorders, which cause genital abnormalities in babies, a finding they claim may pave the way for diagnosis and treatment for those with the condition.

An international team has, in fact, discovered that the alteration of a single gene, called MAP3K1, can cause some male embryos to develop as females, the `American Journal of
Human Genetics` reported.

The conditions occur when the testis or ovary does not develop properly in embryo, causing genital abnormalities in one in 4,500 babies.

In their research, the scientists have identified the gene alteration in a group of patients including two families with several affected members.

They found that the alteration occurred in MAP3K1 gene which plays a role in switching on genes that direct the gonad to become a testis. Males normally have a X and a Y chromosome and females have two X chromosomes.

But the scientists found that the alteration of MAP3K1 gene disrupted normal process of testis development, resulting in a male XY embryo developing female traits, including female genitalia and an overall feminine appearance.

Prof Andrew Sinclair of the University of Melbourne, who led the team, 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.

"To date, we know of only a small number of genes that are involved in gonad development, and can only diagnose about 20 per cent of DSD patients. Based on our study, we believe mutation of the MAP3K1 gene could be responsible for a further
20 per cent of XY DSD cases.

"This is a major breakthrough as the MAP3K1 gene provides new insights into normal testis development and significantly increases the number of DSD cases we can
diagnose in the future," he said.