GSTM1 and von Hippel-Lindau disease: Among patients who underwent CNS-Hb tumor reduction procedures in the cohorts of patients with VHL-CNS-Hb, the costliest long-term complications over 6 months were neurological complications ($97,480; observed in 43.6% of tumor reduction procedures), chronic pain ($93,810; observed in 15.4% of procedures), and seizure ($90,407; observed in 10.3% of procedures; Fig. 2).