ATRX and neuroblastoma: The whole-exome and -genome sequencing of 13 ALT-positive tumors revealed that 8 had an ATRX mutation, 1 had a DAXX mutation, and 1 had a TP53 mutation, whereas 4 were the wild types for ATRX and DAXX. ALT tumors also had significantly higher relative telomere content than that of ALT-negative tumors (p < 0.0001), irrespective of age because ALT NB patients were significantly older at diagnosis than those with ALT-negative NB (p < 0.0001).