To address this question, we analysed BRAF copy number variation (CNV) by digital droplet Polymerase Chain Reaction (ddPCR) on genomic DNA from one BRAFV600E H3.3-K27M tumour (case #2) and from a H3.3-K27M BRAFWT clone derived from this primary tumour in vitro (Supplementary Fig. 6, online resource). The gene discussed is BRAF; the disease is neoplasm.