NF1 and Li-Fraumeni syndrome: This is particularly the case of patients with Li-Fraumeni syndrome (p53+/− mutations), with heterozygous ataxia telangiectasia (ATM+/− mutations) and neurofibromatosis type 1 (NF1+/− mutations) who represent a non-negligible subset of patients (the corresponding prevalence of those three syndromes is 1/4,000, 1/100, and 1/3,000 on average, respectively).