Complete Androgen Insensitivity Syndrome (CAIS):This genetic condition, previously known as testicular feminization syndrome, affects XY fetuses by rendering them unresponsive to androgens, or male hormones. As a result, these individuals are born with external female characteristics. Internally, they possess a short, blind-ending vaginal pouch, lacking fallopian tubes and ovaries, while their testes are located in the abdomen or inguinal canal.CAIS is typically identified during puberty, as affected individuals do not menstruate as expected. Those with the syndrome often lack pubic and underarm hair but have full, thick scalp hair without signs of male-pattern baldness. They are infertile and unable to conceive. Additionally, they face a high risk of certain health issues and may require hormone replacement therapy.The gene responsible for CAIS is located on the X chromosome at the Xq11-q12 band. It encodes the androgen receptor, which is mutated in CAIS, preventing cells from responding to androgens. If a woman carries this mutation on one of her X chromosomes, each of her XY children has a 50% chance of inheriting the syndrome.There are also partial androgen insensitivity syndromes, which often lead to ambiguous genitalia with hypospadias and male breast development. These conditions, including Reifenstein syndrome, also result from mutations in the androgen receptor gene.The term "complete androgen insensitivity syndrome" is now preferred over "testicular feminization syndrome" as it is more scientifically precise and better received by patients and families.
