1. The family histories of 722 infants who were born with spina bifida cystica were studied.
2. The index cases were referred for surgical treatment and were not selected in any way from the genetic point of view.
3. Intensive inquiries were made to obtain a complete family pedigree, including a prospective follow-up of siblings born after the index case.
4. Of 1,256 siblings 85 or 6.8% had gross malformation of the central nervous system: spina bifida cystica in 54, anencephaly in 22, and uncomplicated hydrocephalus in 9.
5. Of 306 children born after the index case 25 (8%) or 1 in 12 were affected.
6. There was a progressive increase in multiple cases in the family with increasing family size. In sibships of five or more, multiple cases occurred in 24.1%.
7. In 118 families cases of gross malformation of the central nervous system were known to have occurred among members of the family other than siblings. Cases occurred in three generations.
8. It is possible that spina bifida cystica might be a recessively inherited condition.
Selection for Treatment in Spina Bifida Cystica
