**Question:** The gene for Breast Cancer (BRCA) is present on chromosome:

A. 17
B. 11
C. 13
D. 12

**Core Concept:**
The BRCA1 and BRCA2 are two well-known genes that play a crucial role in the prevention of breast and ovarian cancers. They are located on chromosomes and are part of the DNA repair system in cells.

**Why the Correct Answer is Right:**
The BRCA1 and BRCA2 genes are indeed involved in DNA repair, which is essential for preventing mutations that can lead to cancer. The correct answer (A) refers to chromosome 17, which is where the BRCA1 gene is located. The BRCA2 gene is located on chromosome 13 (option C), not chromosome 11 (option B), and chromosome 12 (option D) is not involved in BRCA gene location.

**Why Each Wrong Option is Incorrect:**
Option B (chromosome 11) is incorrect because the BRCA2 gene is not located on chromosome 11. Option C (chromosome 13) is incorrect as the BRCA1 gene is located on chromosome 17, not chromosome 13. Option D (chromosome 12) is incorrect as neither the BRCA1 nor BRCA2 genes are located on chromosome 12.

**Clinical Pearl:**
Understanding the location of genes is vital for genetic counseling and testing for inherited diseases like breast and ovarian cancer. Knowledge of the location of BRCA1 and BRCA2 genes helps healthcare providers discuss the risks and potential outcomes of testing with patients who may be considering genetic testing for these genes.

**Correct Answer:** A. 17