Week 1: Disorders of Sex Development Flashcards
Describe the genital indifferent stage

Hypospadias

Anterior and posterior hypospadias

Male epispadias

Typical newborn female vs clitoral hyperplasia

Diagnosis of Atypical genitalia
- Newborn exam
- Newborn screening - CAH (congenital adrenal hyperplasia)
- FISH
- Karyotype
- Labs
Labs for atypical genitalia
- Chemistry
- FSH
- LH
- Testosterone
- Estradiol
- Mullerian inhibiting substance (MIS)
- Specific metabolites if suspecting adrenal hyperplasia
DSD classification system

Sex Chromosome DSD
- 45, X (Turner Syndrome and variant)
- 47, XXY (Klinefelter syndrome and variants)
- 45, X/46, XY (MGD)
Questions

Turner syndrome karyotype
- 45, XO
- One functional X chromosome
- 10% have 46, XY mosaicism -> risk for gonadoblastoma
Pathophysiology of Turner Syndrome
- one functional X chromosome
- Meiotic nondisjunction
- no barr body
What is the most common cause of primary amenorrhea?
Turner syndrome
What Turner Syndrome karyotype carries a risk for gonadoblastoma?
46, XY mosaicism (10% of cases) have risk for gonadoblastoma
What is primary amenorrhea?
Menopause before menarche
Symptoms of Turner Syndrome
Also,
- Pressure difference between the upper and lower extremities > 20 mmHg
- Risk of aortic dissection in pregnancy

Turner Syndrome cardiovascular symptoms
Lab values of Turner Syndrome
- Decreased Estrogen
- Increased FSH
- Increased LH
Streak gonads vs normal ovary

Sex chromosome Disorders of Sexual Development
- 45, X or 46, XY mosaicism Turner Syndrome
- 47, XXY Klinefelter syndrome
- X/46, XY Mixed Gonadal Dysgenesis (MGD)
What is the most common sex chromosome disorder
Klinefelter Syndrome
Klinefelter Syndrome in childhood
- May be a normal physical exam in childhood
- May have developmental delay
Epidemiology of Klinefelter Syndrome
- Most common sex chromosome disorder
- Most common chromosomal cause for hypogonadism and subfertility
What is the most common chromosomal cause for hypogonadism and subfertility
Klinefelter syndrome
Karyotype features of Klinefelter syndrome
- 47, XXY
- Extra X - inactivated -> Barr body present
Klinefelter Syndrome symptoms
- testis atrophy
- Androgynous body shape
- Tall with long extremities
- Gynecomastia
- Female hair distribution
Klinefelter Syndrome Lab findings
- Testis atrophy - abnormal seminiferous tubules and abnormal leydig cell function
- Decreased inhibin B -> increased FSH
- Decreased Testosterone -> increased LH
What is the second most common cause of atypical and “unclassifiable” genital appearance at birth
Mixed Gonadal Dysgenesis
Mixed Gonadal Dysgenesis reproductive organs
Typically a streak gonad on one side and a testis, which may be undescended, on the other side
Most common karyotype of MGD
- 45, X
- 46, XY mosaicism
Mixed Gonadal Dysgenesis concerns
concerns for infertility and gonadoblastoma
Karyotype of Ovotesticular DSD
46, XX
Disorders of gonadal (ovary) development
- Gonadal dysgenesis
- Ovotesticular DSD
- Testicular DSD (eg SRY, dup SOX9, dup SOX3, RSPO1, WNT4)
Ovotesticular DSD was previosly known as?
Previously known as true hermaphroditism
True hemaphroditism is now known as
Ovotesticular DSD
Ovotesticular DSD reproductive organs
- indicates that there is actual testicular and ovarian gonadal tissue
- Most common phenotype is an ovotestis on one side and ovary on other side
Ovotesticular DSD karyotype
Most common karyotype is 46, XX
Ovotesticular DSD most common external anatomy
Most common external anatomy resembles male with severe hypospadias
Question

D. Ovotestis and ovary
Ovotesticular DSD most common external genitalia phenotype

What is the most commonly encountered DSD is?
Congenital adrenal hyperplasia (CAH)
46, XX DSD androgen excess pathologic mechanism
Enzyme deficiency -> decreased steroid -> increased metabolites and lack of ACTH suppression
46, XX DSD androgen excess: What is the most common enzyme deficiency?
Most common enzyme deficiency is 21-hydroxylase (90%)
46, XX DSD androgen excess: 21-hydroxylase deficiency
- Virilization in infancy
- Salt wasting in infancy
- Precocious puberty in childhood
Steroid synthesis pathway

46, XX DSD androgen excess: 11-β Hydroxylase prevalence
5% of cases
46, XX DSD androgen excess: 11-β Hydroxylase symptoms
- Virilization and hypertension
- Hypertension seconday to accumulation of DOC

46, XX DSD androgen excess: 17α-Hydroxylase prevalence
Rare
46, XX DSD androgen excess: 17α-Hydroxylase symptoms
- HTN and lack of sex hormones
- Male - ambiguous and undescended testes
- Female - amenorrhea, lack of secondary sex development

External genitalia of CAH

Question

D. 21α-hydroxylase
Question

C. 11Desoxycortisol
Fetoplacental androgen excess types
- Aromatase (CYP19) deficiency
- Oxidoreductase (POR) deficiency
Placental aromatase deficiency symptoms
- Rare
- Virilization of female infants - clitoral hyperplasia
- May present with virilization of mother in 3rd trimester as fetal androgens cross placenta
- Maternal serum -> increased testosterone, decreased estrogen

Genitalia of Placental Aromatase deficiency

5α-reductase deficiency inheritance pattern
Autosomal recessive
5α-reductase deficiency pathophysiology
46, XY without conversion of T to DHT -> ambiguous genitalia until adolescence when increase T -> virilization and phallic growth

5α-reductase deficiency lab values
- Testosterone normal
- Estrogen normal
- LH may be increased or normal
5α-reductase deficiency genitalia

Androgen insensitivity syndrome

Androgen insensitivty syndrome types
- CAIS
- PAIS
Androgen insensitivty syndrome: CAIS
- Defect in androgen receptor -> typical external female genital exam
- Rudimentary vagina
- Absent internal mullerian structures
- May present with inguinal hernia in childhood
- Amenorrhea
Androgen insensitivty syndrome: CAIS genitals

Kallmann syndrome pathophysiology
Defect with GnRH-releasing neurons and olfactory bulbs
Kallmann syndrome symptoms
- Hyposmia or anosmia
- Infertility in males
- amenorrhea in females
- hypogonadotropic hypogonadism
Kallmann syndrome lab values
- Decreased FSH
- Decreased LH
- Decreased estrogen/testosterone
What is Hyposmia or anosmia
Hyposmia, or microsmia, is a reduced ability to smell and to detect odors. A related condition is anosmia, in which no odors can be detected. Some of the causes of olfaction problems are allergies, nasal polyps, viral infections and head trauma. … Lifelong hyposmia could be caused by Kallmann syndrome.
Case


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