NEUROD2 and embryonal carcinoma: In order to test the pathogenicity of Arg129Trp and His268Gln in mammalian cells and to verify the transposability of tadpole tests to mammalian cells for Glu130Gln (shared by Patients 1 and 5), we took advantage of the fact that ﻿overexpressing human NEUROD2 in P19 mouse embryonic carcinoma cells induces potent neuronal differentiation, a phenotype that relies on binding to DNA through E boxes [43–45] (Fig. 7g).