Disorders Of Sex Development Flashcards
(31 cards)
What is the definition of Disorders of Sex Development (DSD)?
Congenital conditions where chromosomal, gonadal, or anatomical sex is atypical.
What are the three main classifications of DSD?
Sex chromosome DSD, 46 XY DSD, and 46 XX DSD.
What is the global incidence range of DSD?
Between 1 in 2,000 to less than 1 in 20,000 births.
Name three common types of DSD.
Congenital Adrenal Hyperplasia (CAH), Androgen Insensitivity Syndrome (AIS), Mixed Gonadal Dysgenesis (MGD).
At what gestational week does gonadal differentiation begin?
Around 8 weeks of gestation.
Which gene determines testis development?
The SRY gene.
What hormones do Sertoli and Leydig cells produce?
Sertoli cells → AMH; Leydig cells → Testosterone.
What structures are formed from the Wolffian duct?
Epididymis, vas deferens, seminal vesicles.
What structures are derived from the Mullerian duct?
Fallopian tubes, uterus, cervix, upper vagina.
What does the genital tubercle become in males and females?
Males: glans penis; Females: clitoris.
What is the role of dihydrotestosterone (DHT) in genital differentiation?
DHT is essential for development of male external genitalia and prostate.
What is the most common cause of ambiguous genitalia in newborns?
Congenital Adrenal Hyperplasia (CAH).
What is the most common enzyme deficiency in CAH?
21-hydroxylase deficiency.
What are the consequences of 21-hydroxylase deficiency?
Leads to cortisol deficiency, excess androgens, and possibly aldosterone deficiency (salt-wasting).
What chromosomal pattern is seen in 46, XX DSD?
46 XX with normal ovaries but virilised external genitalia due to androgen exposure.
What is Aromatase deficiency, and what does it cause?
Lack of aromatase enzyme causes excess androgens and virilisation.
What are the causes of 46, XY DSD?
Defects in androgen biosynthesis/action, gonadal dysgenesis, AMH defects.
What enzyme defect causes 5-alpha-reductase deficiency?
Mutation in SRD5A2 gene.
What is Androgen Insensitivity Syndrome (AIS)?
X-linked recessive disorder with mutation in androgen receptor gene, causing unresponsiveness to androgens.
Differentiate Complete AIS from Partial AIS.
CAIS: normal female external genitalia, no uterus, blind vagina. PAIS: ambiguous genitalia, variable phenotype.
What is Mixed Gonadal Dysgenesis (MGD)?
Chromosomal mosaicism (e.g., 45 XO/46 XY) with asymmetric gonads.
What chromosomal patterns are seen in MGD?
45 XO/46 XY or 46 XX/46 XY mosaicism.
What are the key features of Turner’s syndrome?
Short stature, primary amenorrhea, streak ovaries, infertility.
What is the karyotype of Klinefelter syndrome?
47 XXY.
