An unimpaired phosphorylation shift of NBN after irradiation has similarly been found in the compound heterozygous NBS patient cells [20] and may indicate that the p.R215W substitution does not strongly disturb the ATM-mediated phosphorylation of NBN at the more distant serine-278 and serine-343 sites. The gene discussed is ATM; the disease is Nijmegen breakage syndrome.