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Androgen insensitivity syndrome (AIS) is a condition that results in the partial or complete inability of the cell to respond to androgens〔〔〔 (''androgenic hormones'') that stimulate or control the development and maintenance of male physiological characteristics by binding to androgen receptors. The unresponsiveness of the cell to the presence of androgenic hormones can impair, or prevent, both the masculinization of male genitalia in the developing fetus, and the development of male secondary sexual characteristics at puberty, though it does not significantly impair the development of female genital or sexual characteristics in females and males with the condition.〔〔 As such, androgen insensitivity syndrome is of clinical significance only when it occurs in individuals that are genetically male (that is, persons with a Y-chromosome, or more specifically, an SRY gene).〔 Clinical phenotypes in genetically male individuals with androgen insensitivity syndrome range from a normal external male body plus mild spermatogenic defect in post-pubertal stages, to a full female external body (although internal gonads are male testes instead of female ovaries) including post-pubertal external female characteristic development, despite the presence of a Y-chromosome.〔〔〔〔〔〔 Both genetically male and genetically female individuals with AIS show reduced to no secondary terminal hair development. In genetic males with AIS, the condition is divided into three categories that are differentiated by the degree of genital masculinization: CAIS, or complete androgen insensitivity syndrome, is indicated when the external genitalia are that of a normal female; PAIS, or partial androgen insensitivity syndrome, is indicated when the external genitalia are partially, but not fully, masculinized; MAIS, or mild androgen insensitivity syndrome, is indicated when the external genitalia are that of a normal male.〔〔〔〔〔〔〔〔〔 Androgen insensitivity syndrome is the largest single entity that leads to 46,XY undermasculinized genitalia in intersex persons.〔 As with other intersex conditions, androgen insensitivity syndrome is independent of both sexual orientation and gender identity. The full spectrum of human sexual orientations has been reported among genetically female and genetically male AIS individuals alike, including: androphilia (i.e. sexual attraction to males) reported by most female-identified genetically-male female-bodied CAIS individuals; gynephilia (i.e. sexual attraction to females) reported even among some female-identified genetically-male female-bodied CAIS individuals in "lesbian" relationships; ambiphilia (bisexuality). Similarly, although AIS individuals may report any gender identity, a female gender identity is the gender identity of most, but not all, genetically-male female-bodied individuals with CAIS. Historically, however, the gender identity of CAIS individuals who identify as female has often been the cause of negative social bias and discrimination once their condition is made public. It is a matter of contention for some whether a CAIS individual with a female gender identity and external female body but genetic male sex should be regarded as "transgender". Some might regard such a person as "transgender" for identifying as female despite their genetic sex being male (even though they have an external female body), or they can be regarded as simply identifying as female in harmony to their external female body (despite their genetic male sex). Much social debate and litigation has resulted as a consequence of both arguments. Male gender identities among a minority of individuals with complete androgen insensitivity syndrome, have also been reported. This has resulted in CAIS individuals who are genetically male with an external female body but a male gender identity (irrespective of sexual orientation). A male gender identity among this minority, however, does not eliminate social contentions among some as to whether these individuals are "transgender", as they might be regarded to be identifying as male despite their external female body (even though their genetic sex is male), or they can be regarded as simply identifying as male in harmony to their genetic male sex (despite their external female body). This contention can be seen even in modern medical literature, where in one case study the genetically male CAIS patient with male gender identity was said to "qualif() as female-to-male transsexual" after undergoing genital reconstruction surgery.〔http://link.springer.com/article/10.1007%2Fs10508-010-9624-1〕 ==Signs and symptoms== AIS is broken down into three classes based on phenotype: complete androgen insensitivity syndrome (CAIS), partial androgen insensitivity syndrome (PAIS), and mild androgen insensitivity syndrome (MAIS).〔〔〔〔〔〔〔〔〔 A supplemental system of phenotypic grading that uses seven classes instead of the traditional three was proposed by pediatric endocrinologist Charmian A. Quigley et al. in 1995.〔 The first six grades of the scale, grades 1 through 6, are differentiated by the degree of genital masculinization; grade 1 is indicated when the external genitalia is fully masculinized, grade 6 is indicated when the external genitalia is fully feminized, and grades 2 through 5 quantify four degrees of decreasingly masculinized genitalia that lie in the interim.〔 Grade 7 is indistinguishable from grade 6 until puberty, and is thereafter differentiated by the presence of secondary terminal hair; grade 6 is indicated when secondary terminal hair is present, whereas grade 7 is indicated when it is absent.〔 The Quigley scale can be used in conjunction with the traditional three classes of AIS to provide additional information regarding the degree of genital masculinization, and is particularly useful when the diagnosis is PAIS.〔〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Androgen insensitivity syndrome」の詳細全文を読む スポンサード リンク
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