Pseudovaginal perineoscrotal hypospadias is a form of male pseudohermaphroditism in which 46,XY males show ambiguous genitalia at birth, including perineal hypospadias and a blind perineal pouch, and develop masculinization at puberty. The name of the disorder stems from the finding of a blind-ending perineal opening resembling a vagina and a severely hypospadiac penis with the urethra opening onto the perineum.

Individuals with androgen insensitivity have a 46,XY karyotype and testes that produce age-appropriate androgen levels but have undermasculinized external genitalia due to defects in androgen action. The phenotype in PAIS varies depending on residual androgen receptor function, ranging from severe undermasculinization presenting as female-like external genitalia to male-appearing genitalia. The typical presentation comprises micropenis, severe hypospadias, and bifid scrotum with or without cryptorchidism (summary by Mongan et al., 2015).

Classic 3-beta-hydroxysteroid dehydrogenase deficiency is an autosomal recessive form of CAH characterized by a severe impairment of steroid biosynthesis in both the adrenals and the gonads, resulting in decreased excretion of cortisol and aldosterone and of progesterone, androgens, and estrogens by these tissues. Affected newborns exhibit signs and symptoms of glucocorticoid and mineralocorticoid deficiencies, which may be fatal if not diagnosed and treated early, especially in the severe salt-wasting form. Moreover, male newborns exhibit pseudohermaphroditism with incomplete masculinization of the external genitalia due to an impairment of androgen biosynthesis in the testis. In contrast, affected females exhibit normal sexual differentiation or partial virilization (summary by Rheaume et al., 1992).

Syndrome with the association of skeletal abnormalities, cutis laxa, craniostenosis, ambiguous genitalia, psychomotor retardation and facial abnormalities. So far, it has been described in two males (maternal first cousins). The mode of inheritance was suggested to be X-linked recessive.

Hypospadias is a common congenital malformation of the penis, affecting approximately 1 in 750 births in Europe. Due to developmental arrest of urethral fusion, the urethral opening is displaced along the ventral side of the penis. The opening can be located glanular, penile, or even more posterior in the scrotum or perineum. Although most children with this condition undergo surgery in their second year of life, serious medical, social, and sexual problems may still exist later in life (summary by van der Zanden et al., 2011). Hypospadias is a feature of several syndromic disorders, including the androgen insensitivity syndrome (300068) and Opitz syndrome (300000). Genetic Heterogeneity of Hypospadias See also HYSP2 (300758), caused by mutation in the MAMLD1 gene (300120) on chromosome Xq28; HYSP3 (146450), a familial form which has been mapped to chromosome 7q32.2-q36.1; and HYSP4 (300856), a susceptibility locus mapped to chromosome Xp11.22 and associated with variation in the DGKK gene (300837).

Nonsyndromic 46,XX testicular disorders/differences of sex development (DSD) are characterized by: the presence of a 46,XX karyotype; external genitalia ranging from typical male to ambiguous; two testicles; azoospermia; absence of müllerian structures; and absence of other syndromic features, such as congenital anomalies outside of the genitourinary system, learning disorders / cognitive impairment, or behavioral issues. Approximately 85% of individuals with nonsyndromic 46,XX testicular DSD present after puberty with normal pubic hair and normal penile size but small testes, gynecomastia, and sterility resulting from azoospermia. Approximately 15% of individuals with nonsyndromic 46,XX testicular DSD present at birth with ambiguous genitalia. Gender role and gender identity are reported as male. If untreated, males with 46,XX testicular DSD experience the consequences of testosterone deficiency.

46,XY females with gonadal dysgenesis have streak gonads but look like normal females at birth. They do not develop secondary sexual characteristics at puberty and do not menstruate. They are chromatin-negative and are usually of normal stature, without the somatic stigmata of Turner syndrome (see 163950) (summary by Mann et al., 1983). For a discussion of genetic heterogeneity of 46,XY sex reversal, see SRXY1 (400044).