Folic acid deficiency can cause severe health problems in offspring, including spina bifida, heart defects and placental abnormalities. A study out today reveals that a mutation in a gene necessary for the metabolism of folic acid not only impacts the immediate offspring but can also have detrimental health effects on the next several generations. The new research, which also sheds light on the molecular mechanism of folic acid (also known as folate) during development, was published today in the journal Cell.
"Although our research focused on genetic mutations which disrupts the break down and metabolism of folic acid, we believe that folic acid deficiency in the diet would have a similar multi-generational impact on health," said Dr Erica Watson from the Centre for Trophoblast Research at the University of Cambridge, who led the study.
The detrimental effects of folic acid deficiency on development are quite well known. As a result, many countries, to include Canada and the US, have implemented folate fortification programmes which require folic acid to be added to cereal products. However, until now, very little was known about how folic acid deficiency caused the diverse range of health problems in offspring.
"Fortification programmes have reduced the risk of health effects but not eliminated them completely," said Dr Watson. "Based on our research, we now believe that it may take more than one generation to eliminate the health problems caused by folate deficiency."
The researchers, from the Universities of Cambridge and Calgary, used mice for the study as they metabolize folic acid very similarly to humans and because folic acid deficiency or mutations in the same genes required to break down folic acid in humans result in similar developmental abnormalities and diseases in mice. This enabled the researchers to explore how the molecular mechanism of folic acid deficiency impacted development, thereby causing health problems.
For the study, the scientists used mice in which a gene called Mtrr was specifically mutated. The gene is key to the normal progression of the folic acid cycle and, when mutated, it results in abnormal folic acid metabolism causing similar effects to dietary folic acid deficiency. The researchers found that when either the maternal grandmother or the maternal grandfather had this Mtrr mutation, their genetically normal grandchildren were at risk of a wide spectrum of developmental abnormalities. These developmental abnormalities were also seen in the fourth and fifth generations of mice.
Through another experiment which involved transferring the embryo from the third generation into a normal healthy female mouse, they discovered that these developmental abnormalities were not passed down genetically. Instead, the serious defects were the result of epigenetic changes which had been inherited.