[Immunogenetic studies of spina bifida--sibling cases in three families]

We reported sibling cases of spina bifida in three families. In the first family, three boys were the products of one mother and different two fathers. They all suffered from spina bifida cystica with various degrees of hydrocephalus. Cyst closure and ventriculo-peritoneal shunt were performed. Elder boys had more severe neurological deficits. In the second family, two boys and one girl were affected. The elder boy had minimum neurological deficit but the younger boy had a severe neurological deficit and hydrocephalus. Cyst closure was performed on both of them but the shunting procedure was not. The girl was normal. In the third family, three girls were affected. The second girl suffered from spina bifida cystica with hydrocephalus and cyst closure was performed. After that ventriculo-peritoneal shunt was done. Other two girls were spina bifida occulta without any neurological deficit. HLA typing, red blood cell antigen typing and chromosome test were studied in three families. There was no evidence of linkage between spina bifida and HLA antigens. Also no relationship between spina bifida and red blood cell antigens. They all had normal chromosomes. We could not make as one material for genetic counseling from above studied three methods.