Flotho et al. [78] first applied SNP array on 16 cases of JMML with normal karyotype and identified large regions of UPD on chromosome 17 spanning approximately 55 Mb, which contained the locus of the NF1 tumor suppressor gene on 17q11.2, in four of five patients with JMML and NF1, but not in other cases without NF1. Inactivating NF1 lesion on both alleles was found by mutational analysis in each case. Here, NF1 is linked to neoplasm.