Check out the UCSC Human Genome Browser Gateway. As an example type AA205474 into the position field and then click on Submit. Then click on one of the BRCA1 occurrences on the left side column. This will bring up a page that includes "Links to sequence". Choose the Genome Sequence link and then choose Submit on the next page. That should finally take you to the BRCA1 gene sequence. Some variants of BRCA1 are linked to an increased risk of breast cancer.