Fig. 1. H3F3A mutations (NM_002107.4) and H3F3B mutations (NM_005324.4).

N, 1, 2, and 3 refer to the N-Helix, Helix-1, Helix-2, and Helix-3 of H3.3, respectively. Upper mutations are encoded by H3F3B, and lower mutations are encoded by H3F3A. Red arrows indicate mutations found in two or more unrelated patients. A few variants, p.N108S, p.P121R, and p.Q125R, were found in the same position in both H3F3A and H3F3B. *p.S146X is only present in an H3F3B alternate transcript not shown here.