Germline results included one case of trisomy 21, consistent with the previous diagnosis of Down Syndrome, one intragenic deletion of TP53 (medulloblastoma, discussed below), TP53 R280S (hypodiploid ALL), TP53 N235S (MPNST), mosaic IDH1 R132H (AML), truncations in PMS2 (high grade glioma), NF1 (low-grade glioma), APC (medulloblastoma), mosaic RB1 (retinoblastoma), BRCA2 (rhabdomyosarcoma), and SDHA (GIST). The gene discussed is PMS2; the disease is gastrointestinal stromal tumor.