These factors include. 1  Living at high latitudes (closer to the polar regions), particularly during winter months. 2  Air quality conditions: high levels of air pollution. 3  Weather conditions: dense cloud covering. 4  The degree to which clothing covers the skin. 5  Use of sunscreen. 6  Skin pigmentation: darker skin types.
A few cases of severe homocysteinemia have been due to rare MTHFR gene mutations (sometimes in combination with a second common MTHFR gene mutation). Symptoms in these patients varied greatly but often involved pronounced neurological symptoms and blood vessel disease.
12 Facts about MTHFR. 1  MTHFR is an enzyme used in an important biochemical process called methylation. The MTHFR gene produces the MTHFR enzyme, but genetic mutations can inhibit this geneâs function. 2  Methylation converts folate and folic acid into the active or âmethylatedâ form your body can use: methylfolate or 5-MTHF.