Unlike Calb and Calr, Parv immunoreactivity was not detected in the youngest DS and NTD cases (Fig. 6I, J, M, N). The first Parv-ir cells were seen in layers V/VI in the oldest DS case (196 wk) (Fig. 6O, P), but not in NTD (174 wk) (Fig. 6K, L). This evidence concerns the gene CALB1 and neural tube defect.