Table 4.

Classification of DSDs, in particular 46,XX DSDs that can result in virilization or male phenotype (18).

DSD category	Examples	Karyotype or genes involved
Sex chromosome DSD	Klinefelter’s syndrome	47,XXY and variants/mosaics
	Turner’s syndrome	45,XO and variants/mosaics
	Ovotesticular DSD	46,XX/46,XY chimerism
46,XY DSD	Disorders of androgen action (androgen insensitivity syndrome)	AR
	Disorders of androgen biosynthesis	CYP11A1, HSD3B2, CYP17A1, StAR, HSD17B3, SRD5A2, POR
	Disorders of testicular development (ovotesticular DSD, testis regression)	DHH, SRY, SF1, WT1, SOX9
	Other syndromic associations of male genital development, isolated hypospadias, cryptorchidism	CXorf6, INSL3, GREAT
46,XX DSD	Disorders of ovarian development (ovotesticular DSD, testicular DSD)	SRY, RSPO1, dup SOX3, dup SOX9*
	Disorders of androgen excess – fetal (congenital adrenal hyperplasia), feto placental (aromatase deficiency) and maternal (virilizing tumors e.g. luteomas)	HSD3B2, CYP21A2, CYP11B1, POR, CYP19
	Other syndromic associations (e.g. cloacal anomalies), Mullerian agenesis/hypoplasia, uterine abnormalities, vaginal atresia (e.g. McKusick-Kaufman), labial adhesions	MKKS

^*Gene duplication detected in the current case of 46,XX karyotype in a young phenotypic male.