This principle has been exemplified in studies showing overlapping phenotypes of the most common hereditary syndromes, LS, and HBOC.10,19-21 One study showed that 1.2% of individuals with suspected LS carried BRCA1/2 P/LP variants (of whom only one third met NCCN HBOC criteria),10 whereas another study found that 22% of individuals with LS met NCCN HBOC testing criteria.19 In the present study, of the 108 patients with P/LP variants, nine (8.2%) were carriers of variants in BRCA1 or BRCA2, of whom Medicare testing criteria identified all BRCA1 carriers but only a subset of BRCA2 carriers. The gene discussed is BRCA2; the disease is Leigh syndrome.