Table 2 An example of a DSD classification.
| Sex chromosome DSD | 46,XY DSD | 46,XX DSD | ||||||
|---|---|---|---|---|---|---|---|---|
| (A) 45,X (Turner syndrome and variants) | (A) Disorders of gonadal (testicular) development | (A) Disorders of gonadal (ovarian) development | ||||||
| 1. Complete gonadal dysgenesis (Swyer syndrome) | 1. Ovotesticular DSD | |||||||
| 2. Testicular DSD (eg, SRY+, dup SOX9) | ||||||||
| (B)47,XXY (Klinefelter syndrome and variants) | 2. Partial gonadal dysgenesis | 3. Gonadal dysgenesis | ||||||
| 3. Gonadal regression | ||||||||
| 4. Ovotesticular DSD | ||||||||
| (C)45,X/46,XY (mixed gonadal dysgenesis, ovotesticular DSD) | (B)Disorders in androgen synthesis or action | (B) Androgen excess | ||||||
| 1. Androgen biosynthesis defect (eg, 17‐hydroxysteroid dehydrogenase deficiency, 5α reductase deficiency, StAR mutations | 1. Fetal (eg, 21‐hydroxylase deficiency, 11‐hydroxylase deficiency) | |||||||
| 2. Fetoplacental (aromatase deficiency, POR) | ||||||||
| (D)46,XX/46,XY (chimeric, ovotesticular DSD) | 2. Defect in androgen action (eg, CAIS, PAIS) | 3. Maternal (luteoma, exogenous, etc) | ||||||
| 3. LH receptor defects (eg, Leydig cell | ||||||||
| hypoplasia, aplasia) | ||||||||
| 4. Disorders of AMH and AMH receptor (persistent mullerian duct syndrome) | ||||||||
| (C) Other | ||||||||
| (C)Other | (eg, cloacal extrophy, vaginal atresia, MURCS, other | |||||||
| (eg, severe hypospadias, cloacal extrophy) | syndromes) | |||||||
While consideration of karyotype is useful for classification, unnecessary reference to karyotype should be avoided; ideally, a system based on descriptive terms (for example, androgen insensitivity syndrome) should be used wherever possible.
AMH, anti‐mullerian hormone; CAIS, complete androgen insensitivity syndrome; DSD, disorders of sex development; MURCS, mullerian, renal, cervicothoracic somite abnormalities; PAIS, partial androgen insensitivity syndrome; POR, cytochrome P450 oxidoreductase.