Hyperhomocysteinemia: Difference between revisions

Evidence exists linking elevated homocysteine levels with [[vascular dementia]]<ref>{{Cite journal|last1=McVeigh|first1=Catherine|last2=Passmore|first2=Peter|date=September 2006|title=Vascular dementia: prevention and treatment|journal=Clinical Interventions in Aging|volume=1|issue=3|pages=229–235|issn=1176-9092|pmc=2695177|pmid=18046875|doi=10.2147/ciia.2006.1.3.229}}</ref> and [[Alzheimer's disease]].<ref>{{cite journal |doi=10.1016/s1474-4422(03)00438-1 |pmid=12849121 |title=Homocysteine and Alzheimer's disease |journal=The Lancet Neurology |volume=2 |issue=7 |pages=425–8 |year=2003 |last1=Morris |first1=Martha Savaria |s2cid=20443022 }}</ref><ref>{{cite journal |doi=10.1159/000326301 |pmid=21474939 |title=Folate and Homocysteine in the Cerebrospinal Fluid of Patients with Alzheimer's Disease or Dementia: A Case Control Study |journal=European Neurology |volume=65 |issue=5 |pages=270–8 |year=2011 |last1=Smach |first1=Mohamed Ali |last2=Jacob |first2=Nelly |last3=Golmard |first3=Jean-Louis |last4=Charfeddine |first4=Bassem |last5=Lammouchi |first5=Turkia |last6=Ben Othman |first6=Leila |last7=Dridi |first7=Hedi |last8=Bennamou |first8=Soufien |last9=Limem |first9=Khalifa |s2cid=7689901 }}</ref><ref>{{cite journal |doi=10.1371/journal.pone.0012244 |pmid=20838622 |pmc=2935890 |title=Homocysteine-Lowering by B Vitamins Slows the Rate of Accelerated Brain Atrophy in Mild Cognitive Impairment: A Randomized Controlled Trial |journal=PLOS ONE |volume=5 |issue=9 |pages=e12244 |year=2010 |last1=Smith |first1=A. David |last2=Smith |first2=Stephen M. |last3=De Jager |first3=Celeste A. |last4=Whitbread |first4=Philippa |last5=Johnston |first5=Carole |last6=Agacinski |first6=Grzegorz |last7=Oulhaj |first7=Abderrahim |last8=Bradley |first8=Kevin M. |last9=Jacoby |first9=Robin |last10=Refsum |first10=Helga |bibcode=2010PLoSO...512244S |doi-access=free }}</ref> There is also evidence that elevated homocysteine levels and low levels of vitamin B6 and B12 are risk factors for [[mild cognitive impairment]] and [[dementia]].<ref name="pmid19769453">{{cite journal |doi=10.1586/ern.09.75 |pmid=19769453 |title=Homocysteine, folate and vitamin B12in neuropsychiatric diseases: Review and treatment recommendations |journal=Expert Review of Neurotherapeutics |volume=9 |issue=9 |pages=1393–412 |year=2014 |last1=Stanger |first1=Olaf |last2=Fowler |first2=Brian |last3=Piertzik |first3=Klaus |last4=Huemer |first4=Martina |last5=Haschke-Becher |first5=Elisabeth |last6=Semmler |first6=Alexander |last7=Lorenzl |first7=Stefan |last8=Linnebank |first8=Michael |s2cid=13246020 |url=https://www.zora.uzh.ch/id/eprint/21178/1/DACH_Zora.pdf }}</ref> Oxidative stress induced by homocysteine may also play a role in [[schizophrenia]].<ref>{{cite journal |doi=10.1007/s11064-012-0707-3 |pmid=22270909 |pmc=3321271 |title=The Oxidative Stress May be Induced by the Elevated Homocysteine in Schizophrenic Patients |journal=Neurochemical Research |volume=37 |issue=5 |pages=1057–62 |year=2012 |last1=Dietrich-Muszalska |first1=Anna |last2=Malinowska |first2=Joanna |last3=Olas |first3=Beata |last4=Głowacki |first4=Rafal |last5=Bald |first5=Edward |last6=Wachowicz |first6=Barbara |last7=Rabe-Jabłońska |first7=Jolanta }}</ref>

Smokeless tobacco is implicated as risk factor for hyperhomocystemia.<ref name="pmid24376761">{{cite journal |vauthors=Iqbal MP, Yakub M |title=Smokeless tobacco use: a risk factor for hyperhomocysteinemia in a Pakistani population |journal=[[PLOS ONE]] |volume=8 |issue=12 |pages=e83826 |date=2013 |pmid=24376761 |pmc=3871626 |doi=10.1371/journal.pone.0083826 |bibcode=2013PLoSO...883826I |url=|doi-access=free }}</ref> Smoking also causes hyperhomocystemia<ref name="pmid21143017">{{cite journal |vauthors=Haj Mouhamed D, Ezzaher A, Neffati F, Douki W, Najjar MF |title=Effect of cigarette smoking on plasma homocysteine concentrations |journal=[[Clinical Chemistry and Laboratory Medicine]] |volume=49 |issue=3 |pages=479–83 |date=March 2011 |pmid=21143017 |doi=10.1515/CCLM.2011.062 |s2cid=34110392 |url=}}</ref>

Genetic defects in [[MTHFR|5-MTHF reductase]] can consequently lead to hyperhomocysteinemia. The most common [[polymorphism (biology)|polymorphisms]] are known as MTHFR C677T and MTR A2756G.<ref>{{cite journal |doi=10.1186/1475-2891-11-2 |pmid=22230384 |pmc=3274435 |title=MTHFR C677T and MTR A2756G polymorphisms and the homocysteine lowering efficacy of different doses of folic acid in hypertensive Chinese adults |journal=Nutrition Journal |volume=11 |pages=2 |year=2012 |last1=Qin |first1=Xianhui |last2=Li |first2=Jianping |last3=Cui |first3=Yimin |last4=Liu |first4=Zeyuan |last5=Zhao |first5=Zhigang |last6=Ge |first6=Junbo |last7=Guan |first7=Deming |last8=Hu |first8=Jian |last9=Wang |first9=Yanni |last10=Zhang |first10=Fumin |last11=Xu |first11=Xin |last12=Wang |first12=Xiaobin |last13=Xu |first13=Xiping |last14=Huo |first14=Yong }}</ref><ref>{{cite journal |doi=10.1371/journal.pone.0033222 |pmid=22470444 |pmc=3310006 |title=Polymorphisms in MTHFR, MS and CBS Genes and Homocysteine Levels in a Pakistani Population |journal=PLOS ONE |volume=7 |issue=3 |pages=e33222 |year=2012 |last1=Yakub |first1=Mohsin |last2=Moti |first2=Naushad |last3=Parveen |first3=Siddiqa |last4=Chaudhry |first4=Bushra |last5=Azam |first5=Iqbal |last6=Iqbal |first6=Mohammad Perwaiz |bibcode=2012PLoSO...733222Y |doi-access=free }}</ref> These polymorphisms occur in about 10% of the world's population.{{Citation needed|date=June 2013}} Elevations of homocysteine can also occur in the rare [[genetics|hereditary]] disease [[homocystinuria]].