testicular feminization syndrome
TRANSCRIPT
TESTICULAR FEMINIZATION SYNDROME; TFM
Alternative titles
ANDROGEN INSENSITIVITY SYNDROME; AIS
ANDROGEN RECEPTOR DEFICIENCY
AR DEFICIENCY
Ruslan Bayramov .MDMedical Genetics department Erciyes university.
To be MAN or not to be MAN!!!AZF-Azoospermia factor
SRY–Sex d. Region
for the SRY gene
Sex-determining Region Y (SRY)
Genital embryology
Pathophysiology
Testicular Feminizing Syndrome
Androgen Insensitivity
Androgen receptor mutations
Androgen receptorGene/locus: AR (Xq11-q12).
Androgen receptor mutations• Over 400 AR mutations have been reported
• 30% of the time, the AR mutation is a spontaneous
• X-linked recessive
Genital embryology
SRY MIF
SRY MIF
INHIBITEDFemale internal structures:
-Fallopian tubes
-Uterus
-Upper portion of
vagina
SRY Testosterone
Genital embryology
SRY Testosterone AR( )
UNDEVELOPEDMale internal structures:
-Seminal vesicles-Epididymis-Ejaculatory duct-Ductus deferens ……
… and Male external structures:
Androgen insensitivity syndrome
- Condition that results in the partial or complete inability of the cell to
respond to androgens
-Clinically significant only when it occurs in genetic males
- X-linked recessive
Ais in XX karyotype
• Phenotype Female • Reduced body hair• Delayed puberty• Tall stature
HETEROZYGOTE HOMOZYGOTE
NO CASE
REPORTED
Three classes of AIS
• CAIS
Complete androgen insensitivity syndrome
• PAIS
Partial androgen insensitivity syndrome
• MAIS
Mild androgen insensitivity syndrome
Complete androgen
insensitivity syndrome
• Phenotypically female
• Symptoms do not appear until puberty
• Absent menses
• External genitalia is normal
• Vaginal depth is short
• Not ovaries - atrophic testes
• Slightly longer limbs and larger hands and feet,
minimal or no acne, larger teeth, well developed
breasts.
• Greater incidence of meibomian gland
dysfunction (dry eye syndromes and light
sensitivity)
Expectations
Bilateral
inguinal
hernia
The risk: Malignant germ cell tumors
Testes may be located intra-
abdominally, at the internal inguinal
ring, or may herniate into the labia
majora.
Partial androgen insensitivity syndrome
• Significant in 46,XY karyotype
• Partially prevented masculinization of the genitalia: penis diminished size, hypospadias, enlarged clitoris.
• Wolffian structures are typically partially or fully developed. (SEED)
• The prostate is small.
• Müllerian remnants are rare, but have been reported.
• Gynecomastia
• High pitched voice
• Micropenis
Chordee Bifid scrotum
Mild androgen insensitivity syndrome
• Impaired virilization or spermatogenesis
• Normal male genital
• Retractile testes
Kennedy Disease
A variant of MAIS
Spinal and bulbar muscular atrophy (SBMA)
Differential diagnoses
• Klinefelter syndrome• Turner syndrome• Smith-Lemli-Opitz syndrome (associated with
intellectual disability• Androgen excess in 46,XX individuals• Mayer-Rokitansky-Küster-Hauser syndrome• Kallmann syndrome (often associated with anosmia)• Frasier syndrome (associated with progressive
glomerulopathy) • Denys-Drash syndrome (associated with nephropathy
and Wilms tumor
A diagnosis of CAIS or Swyer syndrome can be made in utero by comparing a karyotypeobtained by amniocentesis with the external genitalia of the fetus during a prenatal ultrasound.
Swyer syndrome has been estimated to occur in approximately 1 in 30,000 people.
CAIS affects 2 to 5 per 100,000 people who are genetically male.
Reference: 1. Tables from First Aid USMLE step 1 book
2. Wikipedia