| MDPI | Multidisciplinary Digital Publishing Institute |
| MTHFR | 5,10-methylenetetrahydrofolate reductase; Methylenetetrahydrofolate reductase |
| NTDs | Neural tube defects |
| 5,10-methylene-THF | 5,10-methylenetetrahydrofolate |
| 5-methyl-THF | 5-methyltetrahydrofolate |
| NADPH | Nicotinamide adenine dinucleotide phosphate |
| FAD | Flavin adenine dinucleotide |
| Hcy | Homocysteine |
| Met | Methionine |
| MS | Methionine synthase |
| THF | Tetrahydrofolate |
| 5,10-MTHF | 5,10-methylenetetrahydrofolate |
| 5-MTHF | 5-methyltetrahydrofolate |
| SAM | S-Adenosyl-L-methionine |
| SAH | S-Adenosyl-L-homocysteine |
| dTMP | Deoxythymidine monophosphate |
| DNA | Deoxyribonucleic acid |
| CBS | Cystathionine β-synthase |
| SNPs | Single nucleotide polymorphisms |
| Ala | Alanine |
| Val | Valine |
| Glu | Glutamine |
| HHcy | Hyperhomocysteinemia |
| A | Adenine |
| C | Cytosine |
| T | Thymine |
| G | Guanine |
| NO | Nitric Oxide |
| NMDA | N-methyl-D-aspartate |
| PP2A | Protein phosphatase 2A |
| ALP1 | Apolipoprotein 1 |
| EC | Endothelial cells |
| IL-1β | Interleukin 1 β |
| IL-6 | Interleukin 6 |
| IL-8 | Interleukin 8 |
| TNF-α | Tumor necrosis factor |
| ROS | Reactive oxygen species |
| NF-κB | Nuclear factor kappa B |
| CVD | Cardiovascular disease |
| IMH | Intramural hematoma |
| OR | Odds Ratio |
| CI | Confidence Interval |
| BC | Breast cancer |
| HER-2 | Receptor tyrosine-protein kinase erbB-2 |
| PC | Prostate cancer |
| OC | Ovarian cancer |
| CLL | Chronic lymphocytic leukemia |
| ALL | Acute lymphocytic leukemia |
| AML | Acute myeloblastic leukemia |
| CML | Chronic myeloblastic leukemia |
| ASD | Autism Spectrum Disorder |
| Fragile X | Fragile X Messenger Ribonucleoprotein 1 |
| SHANK 3 | SH3 and multiple ankyrin repeat domains 3 |
| CASPR 2 | Contactin-associated protein-like 2 |
| RFC1 | Replication factor C subunit 1 |
| FRα | Folate receptor α |
| PCFT | Proton-coupled folate transporter |
| AD | Alzheimer’s disease |
| EOAD | Early-onset Alzheimer’s disease |
| LOAD | Late-onset Alzheimer’s disease |
| APP | Amyloid precursor protein |
| PSEN1 | Presenilin 1 |
| PSEN2 | Presenilin 2 |
| APOE | Apolipoprotein E |
| aMCI | amnestic Mild Cognitive Impairment |
| SCZ | Schizophrenia |
| MDD | Major Depressive Disorder |
| TRD | Treatment-Resistant Depression |
| FDA | The United States Food and Drug Administration |
| MID | Migraine with comorbid depression |
| PD | Parkinson’s disease |
| L-DOPA | L-3,4-dihydroxyphenylalanine |
| ADHD | Attention deficit hyperactivity disorder |
| DM | Diabetes mellitus |
| T2DM | Type 2 diabetes mellitus |
| IR | Insulin resistance |
| DN | Diabetic nephropathy |
| DR | Diabetic retinopathy |
| DPN | Diabetic peripheral neuropathy |
| GDM | Gestational diabetes mellitus |
| MS | Metabolic syndrome |
| ER | Endoplasmic reticulum |
| NAFLD | Non-alcoholic fatty liver disease |
| NASH | Non-alcoholic steatohepatitis |
| IBD | Inflammatory bowel disease |
| CD | Crohn’s disease |
| UC | Ulcerative colitis |
| U-IBD | Unclassified inflammatory bowel disease |
| DNMTs | DNA methyltransferases |
| RPL | Recurrent pregnancy loss |
| PE | Pre-eclampsia |
| PTB | Preterm Birth |
| LBW | Low birth weight |
| UMFA | Unmetabolized folic acid |
| RA | Rheumatoid arthritis |