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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).

SNPs and mutations in the cystathionine beta-synthase (CBS), methylenetetrahydrofolate reductase (MTHFR), MTR, and MTRR genes contribute to homocystinuria.

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.

See NIH Genetics Home Reference

Variations related to homocystinuria are checked by the genosets gs192 and gs193.