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Mild androgen insensitivity syndrome (MAIS) is a condition that results in a mild impairment of the cell's ability to respond to androgens.〔〔〔 The degree of impairment is sufficient to impair spermatogenesis and / or the development of secondary sexual characteristics at puberty in males, but does not affect genital differentiation or development. Female genital and sexual development is not significantly affected by the insensitivity to androgens;〔〔 as such, MAIS is only diagnosed in males.〔 The clinical phenotype associated with MAIS is a normal male habitus with mild spermatogenic defect and / or reduced secondary terminal hair.〔〔〔〔〔〔 MAIS is one of three types of androgen insensitivity syndrome, which is divided into three categories that are differentiated by the degree of genital masculinization: complete androgen insensitivity syndrome (CAIS) is indicated when the external genitalia is that of a normal female, mild androgen insensitivity syndrome (MAIS) is indicated when the external genitalia is that of a normal male, and partial androgen insensitivity syndrome (PAIS) is indicated when the external genitalia is partially, but not fully masculinized.〔〔〔〔〔〔〔〔〔 Androgen insensitivity syndrome is the largest single entity that leads to 46,XY undermasculinization.〔 ==Signs and symptoms== Individuals with mild (or minimal) androgen insensitivity syndrome (grade 1 on the Quigley scale) are born phenotypically male, with fully masculinized genitalia; this category of androgen insensitivity is diagnosed when the degree of androgen insensitivity in an individual with a 46,XY karyotype is great enough to impair virilization or spermatogenesis, but is not great enough to impair normal male genital development.〔〔〔〔 MAIS is the mildest and least known form of androgen insensitivity syndrome.〔〔 The existence of a variant of androgen insensitivity that solely affected spermatogenesis was theoretical at first.〔 Cases of phenotypically normal males with isolated spermatogenic defect due to AR mutation were first detected as the result of male infertility evaluations.〔〔〔〔 Until then, early evidence in support of the existence of MAIS was limited to cases involving a mild defect in virilization,〔〔 although some of these early cases made allowances for some degree of impairment of genital masculinization, such as hypospadias or micropenis.〔〔〔 It is estimated that 2-3% of infertile men have AR gene mutations.〔 Examples of MAIS phenotypes include isolated infertility (oligospermia or azoospermia),〔〔 mild gynecomastia in young adulthood, decreased secondary terminal hair, high pitched voice, or minor hypospadias repair in childhood.〔〔 The external male genitalia (penis, scrotum, and urethra) are otherwise normal in individuals with MAIS.〔〔〔〔 Internal genitalia, including Wolffian structures (the epididymides, vasa deferentia, and seminal vesicles) and the prostate, is also normal, although the bitesticular volume of infertile men (both with and without MAIS) is diminished;〔 male infertility is associated with reduced bitesticular volume, varicocele, retractile testes, low ejaculate volume, male accessory gland infections (MAGI), and mumps orchitis.〔 The incidence of these features in infertile men with MAIS is similar to that of infertile men without MAIS.〔 MAIS is not associated with Müllerian remnants. 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「Mild androgen insensitivity syndrome」の詳細全文を読む スポンサード リンク
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