There is a low prevalence of AIS, which, in its complete form, only occurs in 20,000 live births. AIS is defined as the inability of the tissues to respond to the action of male hormones, meaning that individuals with XY sex hormones (i.e. 46 XY) are prevented from developing male genitalia. It occurs due to a genetic mutation that codifies the receptor of androgens, and when doctors identify such a mutation, the diagnosis is confirmed. Women carry the gene, but it only develops in men, or, in other words, it is transmitted by a sex-linked recessive gene.
In a review study recently published in the journal Gynaecological Endocrinology, the researchers looked at the most relevant clinical and epidemiological data of AIS to come up with their guidelines. This includes patient follow-up protocols to be applied from birth to adulthood, carried out during childhood and adolescence, as well as additional information for patients. The guidelines are available at the web site of the Biomedical Research Network of Rare Diseases (CIBERER) www.ciberer.es, the Spanish Association of Human Genetics www.aegh.org and the research group on cancer in patients with polymalformation genetic syndromes (www.ct-csgp.org).
So far, it has been difficult to affix guidelines to the syndrome, as it creates such a diversity of symptoms. Clinically, symptoms of AIS can include anything from spermatogenic defects causing infertility in men with otherwise normal genitalia, to individuals who look female in appearance but have not menstruation or female internal genitalia. It can sometimes be problematic identifying the gender of AIS sufferers at birth, and doctors require a more precise diagnosis to determine the sex of the newborn and plan potential treatments.
Professor Mendoza, one of the authors of the study and a researcher at the University of Granada Department of Obstetrics and Gynecology, said that therapy for AIS is based on three pillars: ‘The first step is reinforcing the sexual identity of the subject with the help of psychologists. In cases of sexual ambiguity and determination of female gender, the second step is to perform a gonadectomy (removal of testicles), as they may become cancerous. Finally, it is necessary to administer hormone replacement therapy in case the subject is assigned the female sex. The prognosis of these patients is good if the testicles are timely removed.’