Homocystinuria [Wikipedia], a condition associated with unusually high blood levels of the amino acid homocysteine, is often associated with increased risk of cardiovascular disease, thrombosis, and age-related macular degeneration (ARMD).
More than 24 mutations and variants in the MTHFR gene are known to contribute to homocystinuria.
- rs5742905 I278T Mild clinical homocystinuria which is responsive to vitamin B6
- rs121964972 G307S (common in Irish populations) and unresponsive to pyridoxine (B6) treatment
- rs1801131 is an A1298C substitution in MTHFR
- rs1801133 is a C677T substitution in MTHFR on human chromosome 1p36.3
The following vitamins and drugs have been used to treat patients with homocystinuria.
- vitamin B12 (also known as pyridoxine)
- betaine (also known as trimethylglycine or Cystadane)
- folic acid
- N-Acetylcysteine (experimental, see March of Dimes/McGill clinical trial