In the context of our investigation, we have discerned the presence of PVs, LPs, or VUSs of the genes ATM, BARD1, BRCA1, BRCA2, BRIP1, CDH1, CHEK2, MLH1, MSH2, MSH6, MUTYH, NF1, PALB2, PMS2, PTEN, RAD51C, RAD51D, RAD54L, STK11, and TP53 among BC patients residing in the southernmost region of Thailand. This evidence concerns the gene ATM and breast cancer.