Exam 2: Introduction to Developmental Pathology

Question 1

What are the 3 major parameters for assessment of normal and abnormal sexual development?

Answer 1

Sex chromosome type
Gonadal development
Tubular and external gonadal development

Question 2

What does the reproductive tract differentiate to without proper stimulation?

Answer 2

Female gonadal and external phenotype

Question 3

XX Chromosome

Answer 3

Absence of SRY gene (masculinization) = no TDF/testosterone/AMH
Ovaries develop from undifferentiated gonad
Fallopian tubes, uterus, cervix develop from the mullerian duct

Question 4

XY Chromosome

Answer 4

SRY gene = sex determining region Y on the chromosome that leads to production of testis-determining factor that causes differentiation of embryonic bipotential cells of the primordial gonad develop sertoli cells

Question 5

Sertoli Cells

Answer 5

Contain anti-mullerian hormone
Prevents feminization
Degrades female aspects of the tract (paramesonephric ducts)

Question 6

Leydig cells

Answer 6

Produce testosterone which causes development of male tubular and external genitalia

Question 7

Define: Sex Chromosome DSD

Answer 7

Issue with chromosome number or chimerism

Question 8

Define: Disorders with an XX or XY Genotype

Answer 8

Normal XX or XY genotype with ambiguous phenotype

Question 9

Define: Aneuploidy

Answer 9

Rare in domestic species
XXY/XXX = tortisechell or calico males cats

Question 10

Define: Chimera

Answer 10

Multiple genotypes in one organism
Merging of two zygotes with different genetics
Male, female, or intersex
Phenotypic evidence not always present

Question 11

What is the pathogenesis of freemartinism in cattle?

Answer 11

“Microchimera”
Male/female twins with anastomoses of blood supply
AMH and testosterone suppress feminization = incomplete/partial development of reproductive structures + communication between the vagina and uterus in absent

Question 12

What are the clinical manifestations of freemartinism?

Answer 12

Females typically have remnant seminal vesicles, lack a cervix, and have some degree of ovotestes
92% of female calves will be infertile

Question 13

What clinical test can be done for freemartinism?

Answer 13

Calves 1 - 4 weeks
Normal vaginal length = 13 - 15 cm
Freemartin vaginal length = 5 - 6 cm

Question 14

What is the pathogenesis of XX disorders?

Answer 14

XX female genotype with ambiguous phenotype
Often composed of remnants of degraded male genitalia
Gene expression abnormalities
Excess endogenous or endogenous steroids
Idiopathic

Question 15

Ovarian Cysts

Answer 15

XX disorders of mild degree
Common in all species, can be clinically significant

Question 16

Ovotestes

Answer 16

XX disorder of moderate degree
Hormonal disarrangement (most common in the pig)
Freemartinism

Question 17

Complete sex reversal = female with male genitalia

Answer 17

XX disorder of severe degree
SRY like gene on X chromosome

Question 18

SRY + Disorders

Answer 18

SRY gene is present on Y chromosome
Can have relatively normal testicle formation and some mutation effecting gonadal formation
XY disorder

Question 19

SRY - Disorders

Answer 19

SRY gene is not present on Y chromosome
Can lead to full ovary development or full sex reversal
XY disorder

Question 20

What is the pathogenesis of androgen insensitivity due to loss of receptors?

Answer 20

SRY+ XY Disorder
Testes present: produce testosterone and anti-mullerian hormone
External genitalia develop with female differentiation
Tubular genitalia can be more male due to the tract responding to AMH pending on mutation or dysfunction

Question 21

Cryptorchidism is an example of what disorder?

Answer 21

SRY + XY

Question 22

What is an example of SRY - Disorders?

Answer 22

Swyer syndome
Male karyotype with complete female phenotype
Deletion of SRY gene from the Y chromosome

Question 23

Define: Pseudohermaphrodyte

Answer 23

Gonad geniatalia mismatch

Question 24

Define: Male Pseudoermaphordite

Answer 24

Testicle with female phenotype

Question 25

Define: Female Pseudohermaphrodyte

Answer 25

Ovary with male phenotype

Question 26

Define: True Hermaphrodite

Answer 26

Both gonads present = ovotestis