COLLEGE STATION, Tex. -- A genetic analysis of spina bifida children has revealed the influence of variant choline-metabolism genes in the development of the disease in addition to perinatal consumption of choline-rich foods.
COLLEGE STATION, Tex., Dec. 21 -- A genetic analysis of spina bifida children has revealed the influence of variant choline-metabolism genes in the development of the disease in addition to perinatal consumption of choline-rich foods.
Maternal intakes of choline in the periconceptional period were associated with a reduced risk of spina bifida, as has been previously reported, but there were also genetic effects, reported Richard H. Finnell, Ph.D., of Texas A&M here, and colleagues, online in BMC Medicine.
Compared with mothers who consumed the least amount of choline (290 mg/day or less) those who consumed the most (513 mg/day or more) were less likely (significance unknown) to have an infant with spina bifida (OR=0.60; 95% CI=0.32 to 1.12), their study found.
There was however no link between mothers' dietary consumption of choline-rich food and the genetic risk of spina bifida, said Dr. Finnell and colleagues.
Choline, found in egg yolk, peanuts, sunflower seeds, and cauliflower, is an essential nutrient for the maintenance of cell membrane integrity and methyl metabolism.
"Our study showed genetic-only effects but did not observe gene-nutrient interaction effects associated with choline intake," the authors said. "The results indicate that dietary choline and choline metabolism genes may affect spina bifida risk independently through some other unknown mechanisms."
The study analyzed the genes of 103 infants with spina bifida and 338 unaffected infants. The researchers looked for the presence of two specific single nucleotide polymorphisms (SNPs) in the genes encoding the enzyme human choline kinase A (CHKA) and the enzyme CTP: phosphocholine cytidylytransferase (PCYT1A).
"We believe this is the first study to evaluate DNA sequence variants in the human CHKA and PCYT1A genes for possible association with neural tube defect risk," the authors said.
One SNP of the CHKA gene was associated with a 40% reduced risk for spina bifida compared with the other (odds ratio=0.60; 95% confidence interval=0.38 to 0.94). And one SNP of the PCYT1A gene was linked to a nearly twofold increase in risk compared with the other (OR=1.89; 95% CI=0.97 to 3.67), the study found.
"Reduced risks of spina bifida were found for CHKA SNP hCV1562388, and increased risks were found for [PCYT1A] SNP rs939883," the authors wrote. "These risks, however, were not modified by maternal periconceptional intake levels of dietary choline." However, the result should be interpreted cautiously because of the study's small sample size and limited statistical power, they added.
A further limitation of the study was that it examined only four choline metabolism gene variants, leaving the possibility that there are many more to be discovered that affect spina bifida risk, the authors said.
"Despite its limitations, this study provided initial data indicating a potential association between CHKA and PCYT1A gene variants and spina bifida risk," the authors concluded. "Future studies of additional SNPs within the CHKA and PCYT1A genes should be investigated as potential predictors of spinal bifida risks."