Eligible participants are children and adults with an NTD and their parents residing in the Republic of Ireland, Northern Ireland and the United Kingdom
NTDs are defined to include all forms of spina bifida aperta (meningocele, meningomyelocele), encephalocele, anencephaly, rachischisis, iniencephaly and lipomeningocele. Hydrocephalus, hydranencephaly, dermal sinus and spina bifida occulta do not qualify as NTDs.
For oral clefts, eligible participants are children and adults with a facial cleft in Ireland and their parents.
All families with NTDs or clefts will be recruited for the study.
Those with known syndromes will be excluded or analyzed separately.
Cases for whom both biologic parents are not available will be excluded from some components of triad (case, mother and father) analysis, although the data from the NTD case may be useful for other study components.