Congenital Birth Defects
A study conducted by researchers at Sydney’s Victor Chang Cardiac Research Institute and published in the journal Cell, reveals the cause of congenital defects in newborns. According to the study, it seems that hypoxia combined with a genetic defect during pregnancy increased 10-fold risk of developing an abnormality during embryogenesis. During hypoxia tissues are not sufficiently oxygenated and such disturbances influences the cell and its metabolism. Hypoxia can be caused by several factors in pregnancy, such as uncontrolled diabetes, smoking, altitude, certain medications and anemia. Anemia leads to hypoxia because there is not enough red blood cells to carry oxygen to tissues.
The discovery made by Australian researchers not only clarify the cause of abnormalities but also why they appear only in some people and not others. Professor Sally Dunwoodie, head of the Embryology Laboratory at the institute, Professor at the University of NSW and senior author on the study, said that this discovery clear up many issues so far unclear to scientists. Researchers reached this conclusion by analyzing cases with congenital scoliosis, a deformity of the spine that occurs in 1 in 1000 children. Scoliosis can and gained, especially during childhood, but most shows a genetic predisposition. Scoliosis is characterized by a deviation in the frontal plane spine accompanied by vertebral rotation.
Researchers have found that this combination of factors, ie hypoxia and genetic factors, increased 10-fold risk of developing congenital scoliosis.
This discovery is a step forward in preventing and treating birth defects. By discovering the causes, situations that lead to hypoxia during pregnancy can be avoided and thus can be removed one risk factor. “We hope it will eventually lead to the development of therapeutics to stop tissue defects occurring in the first place.” Said Professor Sally Dunwoodie.
Scientists began by investigating people who had only one functional copy of the gene that causes congenital scoliosis. This was a major risk factor. Then the researchers put to test in mice. Besides genetic factors, it was added the second one, hypoxia, that is rats were exposed on day 21 of pregnancy to 8 hours of low oxygen. Michael Davies, the epidemiologist and senior research fellow in the Discipline of Obstetrics and Gynaecology at the University of Adelaide, explained that oxygen has different effects on the embryo and then the infant in various stages of development. Excess oxygen in the newborn may even cause blindness. Similarly, excess oxygen in early pregnancy can have negative effects. In the third trimester of pregnancy, things are reversed.
One explanation given by Professor Bob Graham, Executive Director of the Victor Chang Cardiac Research Institute, was that not as hypoxia as other environmental factors as anemia, can trigger abnormal gene to be activated. Important to note that mothers who have family history of congenital diseases to be extremely careful during pregnancy.