Answer to Question #270214 in Genetics for hayrunisa

Question

Assume that two individuals with the same mutation in the BRCA1 gene, two of them are heterozygous and the effect of the mutation is dominant. Heterozygous mutations in the BRCA1 gene have been associated with breast cancer development. However one of the individual developped breast cancer but the othe inidividual survided very healthy life untill she died. How would you explain this situation that expected phenotype is not observed from the given genotype?

Answer 1

BRCA1 and BRCA2: The most common cause of hereditary breast cancer is an inherited mutation in the BRCA1 or BRCA2 gene. In normal cells, these genes help make proteins that repair damaged DNA. Mutated versions of these genes can lead to abnormal cell growth, which can lead to cancer.