This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Physiology & Histology, Subject name: Gynaecology & Obstetrics
The Gene present in theca cell and absent in granulosa cell which enables theca cell to produce androgens: 
Select and explain. 
A. CYP17 gene, B. CYP12 gene, C. p53, D. KRAS
A: CYP17 gene
Answer: A: CYP17 gene 
Explanation: Ans. is a, i.e. CYP 17 geneRef: Williams Gynae 3rd/ed, p350"Theca cells express all of the enzymes needed to produce androstenedione. Tins includes high levels of CYP17 gene expression, whose enzyme product catalyzes 17-hydroxylation. This is the rate limiting step in the conversion of progesterone to androgens."