A case of dichorionic twin pregnancy concordant for bilateral cleft lip and palate and discordant for spina bifida; schisis association.

BACKGROUND: The schisis theory suggests that neural tube defect (NTD), cleft lip and palate (CL/P), omphalocele and diaphragmatic hernia are associated to each other more frequently than at the expected random combination rates in a given fetus. However, it is unusual to see schisis-associated defects concordantly in dichorionic twin pregnancy with other schisis-associated and non-associated defects. In addition, the association of lower limb oligodactly with oral cleft and spina bifida has not been reported before.

CASE: A 24-year-old woman with twin gestation at 21 weeks was referred to our unit. At ultrasound examination, bilateral CL/P and single umbilical artery in male fetus, and bilateral CL/P and open lumbar spina bifida in female fetus were revealed. At autopsy, oligodactyly of both lower limbs was demonstrated in the female fetus. The parents had no family history of NTD and CL/P. There was no consanguinity, nor was the mother exposed to teratogens.