Several genetic markers are found in poor prognosis NB, including loss of chromosome 1p, loss of 11q, gain of 17q and, most notably, amplification of the MYCN proto‐oncogene which occurs in about 50% of high‐risk NBs (∼20% of total NBs) (Brodeur, 2003; Maris et al., 2007). The gene discussed is MYCN; the disease is Nijmegen breakage syndrome.