AR and disorder of sexual differentiation: AIS is often suspected to be a common cause of DSD in a 46,XY individual and may be associated with complete feminization of the external genitalia due to a complete lack of AR transcriptional activity (complete AIS [CAIS]) (4), a variable level of feminization/masculinization due to a partial lack of transcriptional activity (partial AIS [PAIS]), or isolated male infertility (mild AIS [MAIS]).