In part, these latter are associated with high-risk clinico-molecular factors (young age, advanced M stage, large-cell/anaplastic histology (LCA), and MYC amplification) but substantial numbers of Grp 3 MB relapse in the absence of these risk indicators [3, 4, 7, 9, 21, 28]. Here, MYC is linked to Leber congenital amaurosis.