Functional testing of DDX3X variants. a–c Representative lateral images of zebrafish embryos at 2 dpf that are either uninjected (a) or injected with human WNT3A without (b) or with (c) human DDX3X show a range of ventralized phenotypes. These were scored according to established criteria as normal, class I, or class II ventralization. No injection condition resulted in severe ventralization (class III or IV) [3]. d DDX3X variants were tested for their effect on increasing WNT3A-mediated ventralization using 550 fg of WNT3A mRNA and 30 pg of DDX3X mRNA per embryo. P values: < 0.0001 (four asterisks); 0.0001 to 0.001 (three asterisks); 0.001 to 0.01 (two asterisks); 0.01 to 0.05 (one asterisk); ≥ 0.05 not significant (ns)