Gastroschisis is caused by the combination of carbon monoxide and protein-zinc deficiencies in mice.

BACKGROUND

Gastroschisis is a rare congenital defect of the abdominal wall. Its occurrence is noted primarily in the offspring of young mothers who often smoke during pregnancy. The incidence of gastroschisis has been increasing in many countries in recent years. The etiology of gastroschisis is not known.

METHODS

Pregnant mice of CD-1 strain were maintained on 17 and 9% protein diets mixed with deficient, normal, or supplemental zinc levels throughout gestation. The dams in each protein-zinc diet group were randomly divided in two groups. One group was exposed to air (control) and the other to 500 ppm carbon monoxide (CO) in air, in environmental chambers, from gestation days (GD) 8-18. The dams were sacrificed by carbon dioxide asphyxiation on GD 18, and data on malformations was collected.

RESULTS

The rates of fetal mortality and malformations were increased by protein and zinc deficiencies. Carbon monoxide exposure also increased fetal mortality. In the low protein group, the rate of fetal mortality was inversely related to the dietary zinc level, and the rate of fetal malformations was highest in the zinc deficient group. The incidence of gastroschisis in the low protein/zinc deficient/CO exposed group was 47%, and 60% of the litters were affected. The incidence of gastroschisis in the rest of the low protein/zinc diets/air or CO groups was 0.

CONCLUSION

The data indicates that gastroschisis is caused by the combination of protein-zinc deficiencies and carbon monoxide exposure during gestation. The finding may be relevant to human populations that experience protein and zinc deficiencies during gestation, and are exposed to CO pollution, or cigarette, or marijuana smoke during pregnancy.