RB1 and retinoblastoma: The Rb1 gene was the most commonly mutated gene, with P/LPSVs were noted in 6/12 (50%) RB patients; P/LPSVs were noted in the NF1 gene in 3 patients: 1/12 (8.3%) patients with RB and 2/3 (66.6%) patients with low-grade glioma.