Two male patients, identified with astrocytoma at 9.2 and 9.7 years after diagnosis of ALL, harbored deleterious variants in ATM. Two SMN patients carried variants in mismatch repair genes: one patient with a mucoepidermoid carcinoma (MSH6) and one individual with an astrocytoma (PMS2); the later also carried an ATM variant. The gene discussed is MSH6; the disease is astrocytoma (excluding glioblastoma).