Table 2. Abnormalities of the fetal vitamin A deficiency (VAD) syndrome (Wilson et al., 1953) present in Rarb-null mutants (Aβ), Rxra-null mutants and in compound Rara/b-, Rara/g- and Rarb/g-null mutants.

(Aα/Aβ, Aα/Aγ and Aβ/Aγ, respectively). #, this abnormality is completely penetrant. NA, not applicable, as the corresponding structure is normally not found at E14.5, the time around which Rxra-null mutants die. From references (Ghyselinck et al., 1997; Lohnes et al., 1994; Kastner et al., 1994). Note that most of the abnormalities seen in Rara/b-null mutants occur at similar frequencies in Rara/b2-mutants (Mendelsohn et al., 1994).