Intensive analysis of the SMARCB1 gene in malignant rhabdoid tumors (MRT) revealed eight of 16 patients with germline genetic variants. Three patients had mosaicism of the variants, which conventional methods might overlook. The prevalence of cancer predisposition in MRT may thus be higher than previously reported.
We next focused on prevalence of germline variants of GATA2 and SAMD9/9L in hematologic disorder with monosomy 7. A total of 25 patients were analyzed, and seven patients with a germline pathogenic GATA2 variant were found. For SAMD9/9L screening, next-generation sequencing was used to detect low-abundance variants and found four novel germline variants. Functional analysis revealed that three out of the four variants showed functional abnormality. GATA2 and SAMD9/9L were sequenced in 25 patients with pediatric hematologic disorders associated with -7, and 40% of them were found to have some pathogenic germline variants in the three genes.