In family B (Fig. 3b), the proband was a 29 years old female CRC patient (III: 4), carrier of a heterozygous exon 3 deletion NC_000002.11 (NM_000251.2):c.(366 + 1_367-1)_(645 + 1_646-1)del in the MSH2 gene (reference sequence NM_000251.2), and four cases of LS associated cancers had occurred in her maternal family. The gene discussed is MSH2; the disease is Leigh syndrome.