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Human development block > Disorders of sexual development > Flashcards

Disorders of sexual development Flashcards

1
Q

What investigations can we do in order to evaluate a new born

A
  1. ) Genetics:
    - karyotype
    - FISH
    - Molecular studies
  2. ) Internal structures:
    - Ultrasound
    - Laparotomy
  3. ) External genitalia
    - Masculinisation score
  4. ) Biochemistry
    - Androgens
    - Steroids
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2
Q

What is ovotesticular disorder?

A
  • Ovarian and testicular tissue in the same individual
  • The presence of structures derived from the Mullerian ducts will depend on production of AMH
  • The presence of structures derived from the Wolffian ducts& the degree of virilisation will depend on the production of testosterone
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3
Q

What are the different types of ovotesticular disorder?

A
  • 46,XX DSD can be caused by mosaic or chimeric forms of SRY+
  • 46, XY DSD can be caused by variants in SRY
  • Sex chromosome DSD mosaic/chimera
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4
Q

Outline 46,XX Testicular DSD

A

-Low testosterone requires replacement, growth hormone treatment or mammoplasty may also be offered
-Most individuals are SRY+, rearrangements around
SOX9 and SOX3 have also been reported
-A minority of individuals present at birth with ambiguous genitalia
-The majority of individuals present after puberty with gynaecomastia, small tests& infertility

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5
Q

Outline 46 XX gonadal dysgenesis

A
  • Failure of ovarian development
  • Internal organs derived from Mullerian structures
  • Female external genitalia
  • Presents with delayed puberty, primary/secondary amenorrhea
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6
Q

What are the different disorders of ovarian development?

A
  • Ovotesticular DSD
  • Testicular DSD
  • Gonadal dysgenesis
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7
Q

What are the different disorders of androgen excess?

A
  • Fetal
  • Fetoplacental
  • Maternal
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8
Q

Outline fetal androgen excess

A
  • Congenital adrenal hyperplasia
  • Exposure to adrenal androgens in utero
  • Mullerian structures develop
  • External genitalia are virilised
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9
Q

What are the characteristics of congenital adrenal hyperplasia?

A
  • Most common form is 21-hydroxylase deficiency
    1. )-‘classic form’= virilisation at birth, may also have salt wasting which is a life-threatening emergency
    2. )Non- classic form’ presents postnatally, may present at puberty with acne, hirsutism & irregular periods
  • Treated with glucocorticoid/mineralocorticoid replacement
  • surgery may be considered for virilisation
  • May need treatment to delay puberty
  • Fertility can be usually preserved
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10
Q

What is 21-hydroxylase

A
  • steroid enzyme

- a cytochrome P450 enzyme that is involved with the biosynthesis of the steroid hormones aldosterone and cortisol

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11
Q

How can maternal androgen excess be caused?

A
  • Luteoma- benign tumour of the ovary which can produce androgens& with virilising consequences for the fetus & mother
  • exogenous androgens
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12
Q

Explain fetoplacental androgen excess

A
  1. ) Aromatase deficiency
    - Converts androgens to oestrogens
    - High levels pf amdrogens can lead to virilisation of XX fetus
    - Can lead to maternal virilisation in pregnancy
  2. ) Cytochrome P450 oxidoreductase deficiency
    - .Electron donor in steroidogenesis
    - Broad range of phenotypes with different variants
    - High levels of androgens in an affected fetus can lead to virilisation of XX fetus
    - Can lead to maternal virilisation
    - Can also lead to XY DSD
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13
Q

What are the characteristics of 46,XY, complete gonadal dysgenesis ?

A
  • Dysgenetic testes
  • Very low testosterone
  • Internal organs derived from Mullerian structures
  • Female external genitalia
  • Presents with delayed puberty/primary amenorrhea
  • Variants in SRY/MAP3K1 account for a significant proportion
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14
Q

What are the characteristics of 46,XY,partial gonadal dysgenesis

A
  • Abnormal development of the testes
  • Low testosterone
  • may/may not have Mullerian structures
  • Ambiguous external genitalia
  • Variants in NR5A1/MAP3K1 account for a significant proportion
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15
Q

Outline gonadal regression

A
  • Complete regression of testicular tissue on one or both sides
  • Abnormal dysgenetic testes
  • Degree of masculinisation reflects duration of testicular function prior to regression
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16
Q

Outline how disorders of androgen action come about

A
  • AR is a nuclear receptor which mediates the effects of the androgens
  • Level of receptor function determines phenotype
  • Appearance of external genitalia, pubertal progression & fertility can be affected
17
Q

What is complete AIS

A

-Testes& adrenal glands produce normal or increased levels of androgens
-Absent or rudimentary Mullerian structures
-Absent or rudimentary Wolffian structures
-External genitalia female but with short vagina
-Present in childhood with masses in the inguinal canals or at puberty with amenorrhea and scant pubic & axillary hair
-The testes are dormant till puberty when they are stimulated to enlarge and gradually increase androgen
production to adult levels.
-Testosterone is aromatised to oestrogen so go into puberty spontaneously
-Normal breast development
-Scant pubic and axillary hair
-Primary amenorrhea

18
Q

How can AIS be managed?

A
  • Surgery/vaginal dilation may be considered after puberty
  • Gonads have a cancer risk~5%
  • Some individuals have gonads removed, generally after puberty, many women report a reduction in libido & loss of sense of well being
  • Hormones replacement after gonadectomy- reproductive, bone, cardiovascular benefits
  • Some individuals opt to retain the testes so that they don’t have to take hormones and in the hope of advances enabling fertility
19
Q

Outline partial AIS

A
  • external genitalia typically female, male or ambiguous’–May present at puberty with clitoromegaly or gynaecomastia
  • May be a role for early gonadectomy & hormones supplementation in individuals raised as females, puberty can be delayed by administration of GnRH agonists
  • May be a role for orchidopexy or hypospadias repair and androgen treatment from puberty in individuals raised as males
20
Q

Outline mild AIS

A
  • external genitalia typically male

- May develop gynaecomastia necessating surgery

21
Q

Outline disorders of androgen synthesis

A
  • 5 alpha reductase deficiency
  • Internal genitalia male
  • Variable appearance of external genitalia: female>ambiguous> predominantly male- small penis, hypospadias
  • Substantial variation on gender identity outcomes
  • During puberty increased androgen levels leads to virilisation
  • If patient raised as a girl may need to consider gonadectomy prior to puberty
22
Q

Outline sex chromosome DSD

A

Turner syndrome and variants
-suspected in females with short stature,lymphedema, cardiac or renal abnormalities,absent or delayed puberty, premature ovarian failure and infertility
Klinefelter syndrome and variants
-suspected in males with hypogonadism, small testes,
azoospermia and gynecomastia, normal or tall stature, speech delay, learning disorders, and behavioural problems.
Chimerism
-individuals with 46,XX/46,XY chimerism may present with external genitalia ranging from typical male to ambiguous to typical female
Mosaicism
-individuals with 45,X/46,XY present as male or female depending on the percentage of 45,X cells

Human development block (35 decks)

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