SM_199b: Sexual Differentiation: Normal and Abnormal Flashcards

1
Q

Describe sex development

A

Sex development

  1. Chromosomal sex
  2. Sex differentiation via ovary-determining genes or testis-determining genes
  3. Gonadal sex
  4. Sexual differentiation via gonadal steroids
  5. Phenotypic sex
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2
Q

Chromosomal sex is developed via ____

A

Chromosomal sex is developed via meiosis

(nondisjunction can occur)

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3
Q

Describe development of gonadal sex

A

Gonadal sex development

  1. First few weeks: gonad starts to develop primordial germ cells in yolk sac
  2. 5-6th week: urogenital ridge develops further and germ cells migrate from hindgut to genital ridge
  3. Differentiation occurs by 8 weeks of differentiation
  4. Ovary develops later after week 10 and requires presence of germ cells
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4
Q

____ is necessary for development of gonads and adrenal glands

A

SF1 is necessary for development of gonads and adrenal glands

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5
Q

____ and ____ must act for testis formation

A

SRY and SOX9 must act for testis formation

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6
Q

___ must be suppressed and ___ active for ovarian development

A

SOX9 must be suppressed and WNT4 active for ovarian development

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7
Q

Describe development of reproductive tract

A

Reproductive development tract

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8
Q

Sertoil cells secrete ____ to promote Mullerian regression

A

Sertoil cells secrete AMH to promote Mullerian regression

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9
Q

Leydig cells secrete ____ and ____ to promote male sexual differentation

A

Leydig cells secrete testosterone and DHT to promote male sexual differentation

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10
Q

Describe AMH (anti-mullerian hormone)

A

AMH (anti-mullerian hormone)

  • Produced by Sertoil cells
  • Regulated by SF1 and SOX9
  • Causes regression of mullerian structures
  • Paracrine effects: AMH from testis causes regression on ipsilateral side
  • Described human mutations of AMH are in 46 XY individuals with persistent mullerian duct syndrome
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11
Q

5 alpha reductase 2 mediates ____ and is required for ____

A

5 alpha reductase 2 mediates conversion of testosterone to dihydrotestosterone and is required for masculinization of external genitalia

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12
Q

Describe phenotypic sex development

A

Phenotypic sex development

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13
Q

Compare and contrast 46 XY and 46 XX development

A

46 XY and 46 XX development

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14
Q

Sex development and gender development are ____

A

Sex development and gender development are different

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15
Q

Disorders of sexual development can present at ___

A

Disorders of sexual development can present at any time

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16
Q

Describe disorders of sexual development

A

Disorders of sexual development

  • Sex chromosome DSD
  • 46 XY DSD: disorders of gonadal development, disorders of androgen synthesis or action
  • 46 XX DSD: disorders of gonadal development, androgen excess
17
Q

Described mixed gonadal dysgenesis

A

Mixed gonadal dysgenesis

  • Variable external genitalia
  • Variable internal genitalia
  • Often asymmetric
  • Gender identity: more male but varies
  • Pubertility / fertility: may produce testosterone and sperm
  • Increased rate of germ cell tumor
18
Q

Describe overtesticular DSD

A

Overtesticular DSD

  • Variable external genitalia
  • Variable internal genitalia
  • Gender identity: varies
  • Puberty / fertility: can produce testosterone or estrogen, subfertility but can produce sperm or eggs
  • Mildly increased rate of germ cell tumor
19
Q

Compare and contrast mixed gonadal dysgenesis and ovotesticular DSD

A

Mixed gonadal dysgenesis and ovotesticular DSD

20
Q

Describe 46 XY DSD

A

46 XY DSD

  • Disorders of gonadal development affect gonadal sex
  • Disorders of androgen synthesis or action affect phenotypic sex
21
Q

Describe complete gonadal dysgenesis

A

Complete gonadal dysgenesis

  • Female-typical external genitalia
  • Mullerian structure present
  • Gender identity: usually female
  • No puberty, no gametes, but can carry pregnancy
  • Increased rate of germ cell tumor
22
Q

Describe partial gonadal dysgenesis

A

Partial gonadal dysgenesis

  • Variable external genitalia
  • Variable internal genitalia
  • Gender identity varies
  • Testosterone and sperm but varies based on testicular function
  • Increased rate of germ cell tumor
23
Q

Compare and contrast complete gonadal dysgenesis, partial gonadal dysgenesis, and ovotesticular DSD

A

Complete gonadal dysgenesis, partial gonadal dysgenesis, and ovotesticular DSD

24
Q

Describe complete androgen insensitivity syndrome

A

Complete androgen insensitivity syndrome

  • Female-typical external genitalia
  • No mullerian structures
  • Gender identity: usually female
  • Testosterone converted to estrogen, no gametes
  • Mildly increased rate of germ cell tumor
25
Q

Describe partial androgen insensitivity syndrome due to AR mutation

A

Partial androgen insensitivity syndrome due to AR mutation

  • Variable external genitalia
  • Gender identity varies
  • Variable testosterone effect, sperm production possible
  • Increased rate of germ cell tumor
26
Q

Describe partial androgen insensitivity syndrome due to 5-alpha reductase deficiency

A

Partial androgen insensitivity syndrome due to 5-alpha reductase deficiency

  • Variable external genitalia
  • Gender identity: more often male
  • Some testosterone at puberty, sperm production possible
  • No increased rate of germ cell tumor
27
Q

Compare and contrast complete androgen insensitivity, partial androgen insensitivity, and 5-alpha reductase deficiency

A

Complete androgen insensitivity, partial androgen insensitivity, and 5-alpha reductase deficiency

28
Q

Describe 46 XX DSD

A

46 XX DSD

  • Disorders of gonadal development affect gonadal sex
  • Androgen excess affects phenotypic sex
29
Q

Compare and contrast testicular DSD and ovotesticular DSD

A

Testicular DSD (XX + SRY) and ovotesticular DSD

30
Q

Describe CAH due to 21 hydroxylase deficiency (salt-wasting)

A

CAH due to 21 hydroxylase deficiency (salt-wasting)

31
Q

Describe congenital adrenal hyperplasia due to 21-hydroxylase deficiency

A

Congenital adrenal hyperplasia due to 21-hydroxylase deficiency

  • Salt-wasting
  • Cortisol deficiency
  • Low Na, high K
  • Lethargy, poor feeding
  • Starts at 5-7 days of life
  • Replace with Florinef and Cortef
  • Gender idnetity is usually female
  • Estrogen and eggs
32
Q

Infant with penoscrotal hypospadias, scrotal tissue rugated on the right but flat on left, right testis palpable in scrotum but left testis nonpalpable

Ultrasound: small mullerian structure present

Most likely diagnosis is

____

A

Infant with penoscrotal hypospadias, scrotal tissue rugated on the right but flat on left, right testis palpable in scrotum but left testis nonpalpable

Ultrasound: small mullerian structure present

Most likely diagnosis is mixed gonadal dysgenesis

(asymmetry)

33
Q

Infant born with prominent clitorophallic structure, single urogenital sinus, fused labioscrotal tissue (no hyperpigmentation or rugation), no palpable gonads

Ultrasound: Mullerian structure present

Karyotype: 46 XX

Most likely diagnosis is ____

A

Infant born with prominent clitorophallic structure, single urogenital sinus, fused labioscrotal tissue (no hyperpigmentation or rugation), no palpable gonads

Ultrasound: Mullerian structure present

Karyotype: 46 XX

Most likely diagnosis is CAH due to 21-hydroxylase deficiency

34
Q

A 16 year old girl presents with primary amenorrhea. She began breast development at age 11 years. Pubic hair is Tanner 2. She has a few wispy axillary hairs. On exam, her external genitalia appears phenotypically female but you palpate 2 inguinal masses.

Most likely diagnosis is ____

A

A 16 year old girl presents with primary amenorrhea. She began breast development at age 11 years. Pubic hair is Tanner 2. She has a few wispy axillary hairs. On exam, her external genitalia appears phenotypically female but you palpate 2 inguinal masses.

Most likely diagnosis is complete androgen insensitivity syndrome