Testicular Development Disorder
Complete Form
The gonads are streak-like tissues, and the external genitalia are completely feminized.
Incomplete Form
The external genitalia are partially feminized or display female-type vulva with clitoromegaly.
LH/HCG Receptor Dysfunction
The phenotype of external genitalia varies. Severe cases exhibit fully feminized genitalia, while mild cases may present with micropenis accompanied by hypospadias.
Androgen Synthesis Abnormalities
Any enzyme dysfunction within the androgen synthesis pathway can disrupt androgen production, leading to 46, XY disorders of sex development.
Steroidogenic Acute Regulatory Protein Deficiency (Congenital Lipoid Adrenal Hyperplasia)
This leads to severe primary adrenal insufficiency, characterized by early-onset glucocorticoid deficiency (e.g., hypoglycemia and hyperpigmentation) and mineralocorticoid deficiency.
P450 Side-Chain Cleavage Enzyme Deficiency
It is widely believed that children with severe inactivation of CYP11A1 are not viable.
3β-Hydroxysteroid Dehydrogenase Type II Deficiency
Clinical presentations include a salt-wasting type and a non-salt-wasting type.
17α-Hydroxylase/17,20-Lyase Deficiency
The phenotype is female, with absent secondary sexual characteristics during puberty, delayed bone age, low-renin hypertension, and hypokalemia with metabolic alkalosis.
17β-Hydroxysteroid Dehydrogenase Type III Deficiency
Individuals are born with female external genitalia but develop progressive masculinization during puberty.
P450 Oxidoreductase Deficiency
Patients with a 46, XY karyotype exhibit feminized external genitalia.
5α-Reductase Type II Deficiency
Cases present with abnormal external genitalia development at birth, such as micropenis or clitoroid-like penis, hypospadias, bifid scrotum, and blind-ending vagina.
Abnormal Androgen Action
Complete Androgen Insensitivity Syndrome (CAIS)
CAIS patients present with a normal female phenotype. The gonads are testes, which may be located in the abdominal cavity, inguinal region, or within the labia majora.
Partial Androgen Insensitivity Syndrome (PAIS)
46, XY individuals exhibit incomplete masculinization. External genitalia may show varying degrees of developmental abnormalities at birth.