 swyer syndrome, or xy gonadal dysgenesis, is a type of hypogonadism in a person whose karyotype is 46,xy. the person is externally female with streak gonads, and left untreated, will not experience puberty. such gonads are typically surgically removed (as they have a significant risk of developing tumors) and a typical medical treatment would include hormone replacement therapy with female hormones. the syndrome was named by gerald swyer, an endocrinologist, based in london, uk. == swyer syndrome as a form of "pure gonadal dysgenesis"== there are several forms of gonadal dysgenesis. the term âpure gonadal dysgenesisâ (pgd) has been used to describe conditions with normal sets of sex chromosomes (e.g., 46,xx or 46,xy), as opposed to those whose gonadal dysgenesis results from missing all or part of the second sex chromosome. the latter group includes those with turner syndrome (i.e., 45,x) and its variants, as well as those with mixed gonadal dysgenesis and a mixture of cell lines, some containing a y chromosome (e.g., 46,xy/45,x). thus swyer syndrome is referred to as pgd, 46,xy, and xx gonadal dysgenesis as pgd, 46,xx.specific disorders of ambiguous genitalia patients with pgd have a normal karyotype but may have defects of a specific gene on a chromosome. ==genetic associations== types include: {| class="wikitable" |- ! type ! omim ! gene ! locus |- | 46,xy gonadal dysgenesis, complete, sry-related |  | sry | yp11.3 |- | 46,xy gonadal dysgenesis, complete or partial, dhh-related |  | dhh | 12q13.1 |- | 46,xy gonadal dysgenesis, complete or partial, with or without adrenal failure |  | nr5a1 | 9q33 |- | 46,xy gonadal dysgenesis, complete, cbx2-related |  | cbx2 | 17q25 |- | 46,xy gonadal dysgenesis, complete or partial, with 9p24.3 deletion |  | | 9p24.3 |} == pathogenesis == the first known step of sexual differentiation of a normal xy fetus is the development of testes. the early stages of testicular formation in the second month of gestation requires the action of several genes, of which one of the earliest and most important is sry, the sex-determining region of the y chromosome. mutations of sry account for many cases of sw
Congenital_disorders_of_genital_organs Gynaecologic_disorder Intersex_and_medicine Syndromes