Disorders of Sex Development (DSD)

Understanding the complex relationship between chromosomal, gonadal, and phenotypic sex.

Disorders of sex development (DSD) occur when there is a mismatch between phenotypic sex and gonadal sex.

G Gonadal Sex

Determined by the presence of testes or ovaries and usually corresponds to the chromosomal sex (XY = testes, XX = ovaries).

P Phenotypic Sex

Refers to the appearance of external genitalia, which is influenced by hormonal exposure during development (e.g., testosterone, dihydrotestosterone, estrogen).

When these two do not align, the individual may have:

• Male gonads (testes) but female-appearing genitalia, or
• Female gonads (ovaries) but ambiguous or virilized genitalia.

Historical Terminology

“Hermaphroditism” and “pseudohermaphroditism” were previously used.

Modern terminology

Intersex or disorders of sex development (DSD).

Causes include:

• Genetic mutations affecting sex differentiation (e.g., androgen insensitivity syndrome)
• Enzyme deficiencies affecting steroid hormone synthesis (e.g., congenital adrenal hyperplasia)
• Chromosomal anomalies (e.g., mixed gonadal dysgenesis, mosaicism)

Clinical Importance

Recognition & Care

Early recognition is crucial for gender assignment, hormonal therapy, fertility counseling, and psychological support.

Evaluation Process

Evaluation involves karyotyping, hormonal assays, imaging, and sometimes genetic testing.

Medical Education Resource © 2024