*Article*

### **Genetic Variants in Folate and Cobalamin Metabolism-Related Genes in Pregnant Women of a Homogeneous Spanish Population: The Need for Revisiting the Current Vitamin Supplementation Strategies**

**Gemma Rodriguez-Carnero 1,2,†, Paula M. Lorenzo 1,3,†, Ana Canton-Blanco 1,2, Leire Mendizabal 4, Maddi Arregi 4, Mirella Zulueta 4, Laureano Simon 4, Manuel Macia-Cortiñas 5, Felipe F. Casanueva 3,6 and Ana B. Crujeiras 1,3,\***


**Abstract:** Polymorphisms of genes involved in the metabolism and transport of folate and cobalamin could play relevant roles in pregnancy outcomes. This study assessed the prevalence of genetic polymorphisms of folate and cobalamin metabolism-related genes such as MTHFR, MTR, CUBN, and SLC19A1 in pregnan<sup>t</sup> women of a homogeneous Spanish population according to conception, pregnancy, delivery, and newborns complications. This study was conducted on 149 nulliparous women with singleton pregnancies. Sociodemographic and obstetrics variables were recorded, and all patients were genotyped in the MTHFR, MTR, CUBN, and SLC10A1 polymorphisms. The distribution of genotypes detected in this cohort was similar to the population distribution reported in Europe, highlighting that more than 50% of women were carriers of risk alleles of the studied genes. In women with the MTHFR risk allele, there was a statistically significant higher frequency of assisted fertilisation and a higher frequency of preeclampsia and preterm birth. Moreover, CUBN (rs1801222) polymorphism carriers showed a statistically significantly lower frequency of complications during delivery. In conclusion, the prevalence of genetic variants related to folic acid and vitamin B12 metabolic genes in pregnan<sup>t</sup> women is related to mother and neonatal outcomes. Knowing the prevalence of these polymorphisms may lead to a personalised prescription of vitamin intake.

**Keywords:** vitamin B9; vitamin B12; pregnancy; newborn; polymorphism; one-carbon metabolism; MTHFR; MTR; CUBN; SLC10A1
