The most common cancer predisposition syndromes (CPSs) were neurofibromatosis type 1 (caused by constitutional LPV/PV in NF1; 1.5%), Li–Fraumeni syndrome (TP53; 1.2%), constitutional MMR deficiency or Lynch syndrome (MLH1, MSH2 and MSH6, 1.1%; PMS2 was not included in the gene panel at the time of analysis), ataxia–telangiectasia and ATM heterozygous carriers (ATM, 0.9%), neurofibromatosis type 2 (NF2, 0.8%), DICER1 syndrome (DICER1, 0.6%) and rhabdoid tumor predisposition syndrome 1 (SMARCB1, 0.4%). The gene discussed is ATM; the disease is mismatch repair cancer syndrome 1.