CELSR1 and neural tube defect: Rare variants in CELSR1 have previously been reported in both open and closed NTD types.38, 39, 40 Two previous NTD cases have been reported to be doubly heterozygous either for CELSR138 or DVL2. 44Celsr1 homozygous mutant (Celsr1Crsh/Crsh) mice show craniorachischisis,9 suggesting that the CELSR1 gene is likely to be implicated in both human and mouse NTD etiology.