How is the breast cancer gene inherited?
The inheritance of the BRCA-1 and BRCA-2 mutation is subject to a so-called autosomal dominant inheritance. This means that the BRCA mutation present in one parent is passed on to the offspring with a 50% probability. This occurs independently of gender and can also be inherited from the father. If no mutation is detected in someone, he or she cannot pass it on.
How common is the breast cancer gene in the population?
A BRCA mutation is very rare. Only about one in 500 people carries a mutation in the BRCA1 gene and only about one in 700 people carries a mutation in the BRCA2 gene. Only 5-10% of breast cancers are due to an inheritable cause, with only 25% of cases having a BRCA-1 or BRCA-2 mutation
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