295possibly abnormally positioned testes. Patients with 46,XY DSD due to 17 β-HSD3
defi ciency usually do not have virilization of external genitalia during embryogen-
esis; however, these patients exhibit some degree of virilization during peripubertal
period as a result of extra-glandular conversion of androstenedione to testosterone
by 17β-HSD5, an isoenzyme, which is possibly induced by some environmental
factor during adolescence. The index patient was assigned female gender as proba-
bly mild genital ambiguity would have been overlooked at birth; however, during
adolescence she had appearance of pubic hair, phallic enlargement, and some degree
of breast development. Sometimes patients with 17β-HSD3 and 5α-reductase defi -
ciency may exhibit reversal of gender identity and role during adolescence.
Nevertheless, she did not have any change in gender role and orientation. Absence
of uterus is characteristic of androgen biosynthetic defects associated with 46,XY
DSD which was also observed in the index patient. Corrective surgery is indicated
in concordance with the gender role and behaviour of an individual as well as the
extent of virilization. The index patient had gender identity, role, and orientation as
a female and the degree of virilization of external genitalia was mild (EMS 2);
therefore, a decision to feminize her was propounded and corrective surgery was
done accordingly.
9.3 Clinical Rounds
- What are the “ disorders of sex development ?”
The term “disorders of sex development” (DSD) refers to congenital disor-
ders associated with discordance in chromosomal, gonadal, or anatomical
(phenotypic) sex of an individual. Previously, the terms intersex, pseudoher-
maphrodite, and hermaphrodite were used to describe individuals with geni-
tal ambiguity. However, these terms were derogatory and lacked scientifi c
basis. The new classifi cation is based on karyotype and includes disorders
associated with defects in chromosomal, gonadal, or anatomical sex, even in
the absence of genital ambiguity.- What is the basis of origin of chromosomal DSD?
Chromosomal DSD occurs as a result of nondisjunction of homologous chro-
mosomes (sister chromatids) either during meiosis/mitosis or due to chimerism.
Normally, during the period of anaphase, there is separation of sister chroma-
tids with equal distribution of genetic material into two chromatids. The failure
to separate or unequal distribution of genetic material into two chromatids
results in aneuploidy. Meiotic nondisjunction results in disorders like classical
Klinefelter syndrome (47,XXY) and Turner syndrome (45,XO), whereas
mitotic nondisjunction results in mosaic variants of Turner syndrome
(45,XO/46,XX) and Klinefelter syndrome (46,XY/47,XXY). Ovotesticular
DSD (46,XX/46,XY) occurs due to sex chromosome chimerism.9 Disorders of Sex Development