What karyotype is typical in a patient with androgen insensitivity syndrome?

Androgen insensitivity syndrome (AIS) is a condition that affects sexual development and is caused by a genetic mutation that leads to the body's inability to respond to androgens, which are male hormones. Patients with this condition typically have a male karyotype, which means they possess one X chromosome and one Y chromosome.

In AIS, although the karyotype is 46,XY, the presence of the Y chromosome is significant as it typically indicates the formation of male gonads (testes). However, due to the insensitivity to androgens, individuals with this karyotype develop female external characteristics and may have varying degrees of female genital development while lacking a functional uterus or ovaries.

The presence of a Y chromosome is critical in diagnosing AIS, as it distinguishes the condition from disorders associated with other karyotypes like 45,X (Turner syndrome), 46,XX (which typically indicates a genetically female individual), or 47,XXX (which is a variant of female chromosome pattern). Thus, the karyotype typical in a patient with androgen insensitivity syndrome is 46,XY, reflecting the presence of the Y chromosome necessary for male development, albeit with the atypical manifestation due to androgen insensitivity.