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.
The MTHFR gene (not to be confused with the MTHFR enzyme) is one of 20,000 genes in the human body. It can be thought of as âmaster instruction sheetâ for producing the MTHFR enzyme. However, genetic mutations or variations often occur at the MTHFR gene.