The term gonadal dysgenesis applies to persons who have streak gonads rather than ovaries. Affected individuals lack germ cells and show hypogonadism at puberty. Affected individuals undergo breast development and feminization at puberty. Despite pubertal feminization, some individuals with androgen insensitivity show clitoral enlargement and labioscrotal fusion. In complete androgen insensitivity, antim llerian hormone is synthesized as in the normal testis.
Affected individuals undergo breast development, but areolae are often pale and underdeveloped.
Such individuals are said to have incomplete androgen insensitivity. The number of common mendelian diseases in which the molecular genetics are sufficiently understood to allow this sort of diagnosis is now large and rapidly expanding. Today, most of the direct tests rely on the ability to amplify quickly and efficiently a specific region of DNA by using the polymerase chain reaction. The polymerase chain reaction greatly facilitates cloning of individual genes from a patient sample. It allows amplification of a defined DNA segment, even from a single cell, by 105107 copies in about 3 hours.