Neural tube defects (NTD) together with cardiovascular system defects are the most common malformations in the Polish population (2.05-2.68/1000 newborns). They arise during early embryogenesis and are caused by an improper neural groove closure during the neurulation process. NTD can arise from the influence of specific environmental factors on the foetus. The genetic factor is also very important, because NTDs have multigenetic conditioning. It was suggested that genes connected with the regulation of neurulation could also be involved in NTD aetiology, especially when their deletion or modification leads to neural tube defects in the mouse model. Examples are genes from the PAX family, T (Brachyury), BRCA1 and PDGFRA genes.