Sex Determination Flashcards
Describe the pathway that results in gonad formation from the division of the urogenital ridge to the formation of the ducts and urinary system
Germ cells migrate
Form nephrogenic, gonadal regions
Nephrogenic region
-Wolffian, Mullerian ducts and urinary system
Gonadal region
- starts as undifferentiated gonadal ridge
- transcription factors => bipotential gonad
How do the testes form
-What 3 genes are vital in this
SRY gene
-normally on Y but can be exchanged with PAR1 and end up on X
SOX9 gene (C17)
- promotes formation
- 2 copies needed for function
DAX1 gene (X)
- repress formation
- 2 copies needed for function
- DO NOT WANT THIS TO BE ACTIVE IN TESTES FORMATION
How do the ovaries form
- what chromosome is vital for this
- what happens in Turners
Both X expressed, no dosage compensation
Turners XO => no functional ovaries
How are the male reproductive organs formed
Testes produce
- testosterone => DHS => lower 1/3 (penis, scrotum, prostate)
- AMH => Mullerian regression
- Wolffian => epididimus, vas, seminal vesicle
How are the female reproductive organs formed
Ovary produces
-estrogen => Mullerian development => FT, uterus, upper vagina
OCCURS INDEPENDENTLY OF OVARY
Lack of testosterone => Wolffian regression
No DHS => lower 1/3 (lower vagina, vulva, clitoris
What is ovotesticular DSD
What are the signs and symptoms of
-extra ovarian tissue
-extra testicular tissue
Ovarian and testicular tissue in same gonad/one of each
- presence of Mullerian structures dependent on AMH production
- presence of Wolffian structures dependent on T production
Ovarian tissue
-gynecomastia, menstruation
Testicular tissue
-hirsuitism, increased tumour risk
What is 46XX Testicular DSD
What are the signs and symptoms
How would you manage this
SRY on X => testes formation
2 copies of DAX1 => testes dev supressed
Variable presentation but SMALL TESTES
Testosterone
Mammoplasty (female characteristics)
GH (T stimulates GH)
What is 46XX Gonadal dysgenesis DSD
What are the signs and symptoms
How would you manage this
No ovaries => no estrogen,
-No Mullerian ducts
Female ext genitalia
Delayed puberty
Amenorhhea, lack of O
Oestrogen, progesterone
What is 46XY Complete gonadal dysgenesis
What are the signs and symptoms
No testes => no testosterone, no AMH
-No Wolffian ducts
Female ext genitalia, undeveloped int genitalia
Delayed puberty
Primary amenorrhea
What is 46XY partial gonadal dysgenesis
What are the signs and symptoms
Partially developed testes => some testosterone, some AMH
- some Wolffian development, some Mullerian regression
- some ext genitalia dev
Ambiguous ext genitalia
What is gonadal regression
What are the signs and symtptoms
Complete regression of testicular tissue
Masculinization reflects amount of testicular function prior
What is Klinefelters XXY
What are the signs and symptoms
Undescended/pea sized testicles Tall Gynecomastia, femenine properties Infertile Lack of 2ndary male characteristics
What are the signs and symptoms of SRY translocation
How would you manage this
Male with XX Short Small testes Gynecomastia Infertility
Testosterone
What is the pathophysiology behind 5alpha reductase deficiency
What are the signs and symptoms
-how do they vary before and after puberty
Needed to convert T => DHS
Before puberty
- Ext genitalia variable/female
- Int genitalia male
After puberty (increased T) -virilization of ext genitalia
When can you get a hyperandrogenic state
What are the consequences on the fetus and mother
Aromatase deficiency => cannot convert A to O
CYP450 deficiency => excess A
Luteoma
XX fetus virilized
Maternal virilization
