The cause of many disorders of sex development remains a mystery, study finds

17 August 2011

The cause of a large number of disorders of sex development (DSD) remains unknown, with 43 percent of patients with the condition not receiving a definitive diagnosis, research by Murdoch Childrens Research Institute and The University of Melbourne has found.

Disorders of sex development occur when the development of male or female genitals in the embryo is atypical. One in 4500 people is born with genitals where the sex is not clear at birth. Some reports state that birth anomalies such as anomalies of the penis are increasing, and now occur in 1 in 125 boys. This condition is associated with lifelong psychological issues, reproductive problems and increased gonad cancer risks.

The final body appearance of someone with DSD with does not always correspond with what is dictated by the genes. In other words, a person with DSD may have XY chromosomes (male) but have biological characteristics of the female sex.

An analysis of 199 DSD patients at the Royal Children's Hospital found 54% had XY sex chromosomes, 32% had XX sex chromosomes and 14% had mixed sex chromosomes, but a definitive cause for the sex development disorder was made in just over half of all patients assessed.

The analysis found that a cause was identified in most patients with XX chromosomes, but that more than two-thirds of those with XY chromosomes never received a definitive diagnosis.

Dr Jacky Hewitt, an endocrinologist at Murdoch Childrens Research Institute, said the analysis highlights the need for more research into the cause of these disorders.

"Making a correct determination of gender is important both for treatment purposes, as well as for the emotional well-being of the child. As the underlying diagnosis can affect the cancer and infertility risk of patients, decisions of treatment are made according to diagnosis," she said.

"It's a great concern that some children with this disorder have no accurate diagnosis. More research into the cause of these disorders will alleviate uncertainty surrounding the conditions, helping us to develop better treatments, and may assist with prevention in the future."

The research findings were presented at the annual meeting of the North American Society for Pediatric and Adolescent Gynecology in Chicago.