http://brcaprevivor.blogspot.in/2013/11/23andnotme-critical-evaluation-of.html
A woman "generally" used 23&Me ( https://www.23andme.com/en-int/) and of all other information, also evaluated herself for the risk of breast cancer. 23&Me screens for only 3/3664 possible mutations in the BRCA1 and BRCA2 genes that could be associated with higher risk for breast cancer (hot-spot mutation testing). The woman came negative by 23&Me test. This led her to false sense of security from disease risks. While 23&Me DNA test isn’t for diagnostics, a lay person can fall in the trap of treating its BRCA analysis at par with that of a diagnostic lab test. Eventually when the same woman got the test done by Myriad, pathogenic mutations were identified leading to her mastectomy.
This patient blog drives home an important point, that definition of "hotspot" is very fluid and it varies from Lab to Lab. It may happen that a lab screens only 3% while another lab screens 60% of pathogenic mutations in a gene, while both claim hotspot sequencing. Unless we know, how exhaustive their screening test is, merely getting “hotspot” test done isn’t enough. This is true especially for tumor suppressor genes such as TP53, PTEN etc.