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.
Based on work at Mayo Clinic, it now appears that the core pathogenic factor in SIH is decreased CSF volume rather than decreased CSF opening pressure. Patients can have normal CSF pressure and yet have this syndrome, Dr. Mokri says. Even orthostatic headache, the most common symptom of SIH, appears to vary.