This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous (Obs), Subject name: Gynaecology & Obstetrics
Commonest cause of primary amenorrhea: 
Select and explain. 
A. Gonadal dysgenesis, B. Mullerian agenesis, C. Androgen insensitivity syndrome, D. Stein Levinthal syndrome
A: Gonadal dysgenesis
Answer: A: Gonadal dysgenesis 
Explanation: Ans. A. Gonadal dysgenesis.Gonadal dysgenesis does not equate with turner's syndrome. There are many causes of gonadal dysgenesis in the female, most of which relate to abnormalities involving X chromosome e.g. Turner syndrome, turner mosaic, 46XY gonadal dysgenesis. 25% of girls with gonadal dysgenesis have 46XX karyotype. Turner syndrome is the most common form of gonadal dysgenesis