ATM and breast cancer: Bulgarian population had a higher number of deleterious variants in ATM and MUTYH; Ashkenazi Jewish population contained the three well-known BRCA founder mutations [BRCA1 185delAG(c.68_69del), 5382insC(c.5266dup), and BRCA2 6174delT(c.5946del)] (Abeliovich et al, 1997); of the only six deleterious variants in Estonian population, two were in ATM; BRCA2 c.771_775del (999del5), a founder mutation in Icelander for breast cancer (Tulinius et al, 2002), was not but BRCA2 c.8904del was present in the Icelander population.