Association of maternal weight with <i>FADS</i> and <i>ELOVL</i> genetic variants and fatty acid levels- The PREOBE follow-up

<div><p>Single nucleotide polymorphisms (SNPs) in the genes encoding the fatty acid desaturase (<i>FADS</i>) and elongase (<i>ELOVL</i>) enzymes affect long-chain polyunsaturated fatty acid (LC-PUFA) production. We aimed to determine if these SNPs are associated with body mass index (BMI) or affect fatty acids (FAs) in pregnant women. Participants (n = 180) from the PREOBE cohort were grouped according to pre-pregnancy BMI: normal-weight (BMI = 18.5–24.9, n = 88) and overweight/obese (BMI≥25, n = 92). Plasma samples were analyzed at 24 weeks of gestation to measure FA levels in the phospholipid fraction. Selected SNPs were genotyped (7 in <i>FADS1</i>, 5 in <i>FADS2</i>, 3 in <i>ELOVL2</i> and 2 in <i>ELOVL5</i>). Minor allele carriers of rs174545, rs174546, rs174548 and rs174553 (<i>FADS1</i>), and rs1535 and rs174583 (<i>FADS2</i>) were nominally associated with an increased risk of having a BMI≥25. Only for the normal-weight group, minor allele carriers of rs174537, rs174545, rs174546, and rs174553 (<i>FADS1</i>) were negatively associated with AA:DGLA index. Normal-weight women who were minor allele carriers of <i>FADS</i> SNPs had lower levels of AA, AA:DGLA and AA:LA indexes, and higher levels of DGLA, compared to major homozygotes. Among minor allele carriers of <i>FADS2</i> and <i>ELOVL2</i> SNPs, overweight/obese women showed higher DHA:EPA index than the normal-weight group; however, they did not present higher DHA concentrations than the normal-weight women. In conclusion, minor allele carriers of <i>FADS</i> SNPs have an increased risk of obesity. Maternal weight changes the effect of genotype on FA levels. Only in the normal-weight group, minor allele carriers of <i>FADS</i> SNPs displayed reduced enzymatic activity and FA levels. This suggests that women with a BMI≥25 are less affected by <i>FADS</i> genetic variants in this regard. In the presence of <i>FADS2</i> and <i>ELOVL2</i> SNPs, overweight/obese women showed higher n-3 LC-PUFA production indexes than women with normal weight, but this was not enough to obtain a higher n-3 LC-PUFA concentration.</p></div

Characteristics of the population.

<p>Characteristics of the population.</p

Associations between plasma proportions of PUFAs and <i>FADS</i> and <i>ELOVL</i> polymorphisms.

<p>Associations between plasma proportions of PUFAs and <i>FADS</i> and <i>ELOVL</i> polymorphisms.</p

Substrates and products of enzymatic indexes according to maternal SNPs and LC-PUFA levels in plasma.

<p>Substrates and products of enzymatic indexes according to maternal SNPs and LC-PUFA levels in plasma.</p

<i>FADS1</i>, <i>FADS2 and ELOVL2</i> enzymatic indexes according to maternal SNPs and LC-PUFA levels in plasma.

<p><i>FADS1</i>, <i>FADS2 and ELOVL2</i> enzymatic indexes according to maternal SNPs and LC-PUFA levels in plasma.</p