In humans, homozygous mutations in VANGL2 are embryonic lethal and cause craniorachischisis, a very severe neural tube defect encompassing anencephaly and bony defects of the spine in mice (89), whereas heterozygous VANGL2 mutations are embryonic lethal and detected in miscarried human fetuses with severe cranial neural-tube defects (90). The gene discussed is VANGL2; the disease is craniorachischisis.