ZIC4 and neural tube defect: To verify the hypomethylated CpG sites in ZIC4 that were identified in the above microarray data, the methylation status of CpG sites in the ZIC4 promoter region and 5′ UTR was assayed with the Sequenom EpiTYPER platform with DNA extracted from the neural tissues of subjects consisting of 80 NTD cases and 32 controls.