Rs1801133 Explained

Name 1:	C677T
Name 2:	Ala222Val
Name 3:	A222V
Rsid:	1801133
Gene:	MTHFR
Chromosome:	1
Alzgene Geneid:	70
Alzgene Polyid:	155
Szgene Geneid:	4
Szgene Polyid:	31

C677T or rs1801133 is a genetic variation—a single nucleotide polymorphism (SNP)—in the MTHFR gene.

Among Americans the frequency of T-homozygosity ranges from 1% or less among people of sub-Saharan African descent to 20% or more among Italians and Hispanics.^[1]

It has been related to

• schizophrenia^[2]
• Alzheimer's disease^[3]
• depression^[4]
• autism^[5]
• spina bifida.

In 2000 association studies on oral clefts, Down syndrome, and fetal anticonvulsant syndrome were either unreplicated or had yielded conflicting results.

Related genetic variants

A1298C is a SNP in the same gene.Studies have investigated the combined effect of C677T and A1298C.^[6]

Notes and References

1. . 5,10-Methylenetetrahydrofolate reductase gene variants and congenital anomalies: a HuGE review . . 151 . 9 . 862–867 . May 2000 . 10791559 . 10.1093/oxfordjournals.aje.a010290. free .
2. Web site: Meta-Analysis of All Published Schizophrenia-Association Studies (Case-Control Only) for (C677T) polymorphism, MTHFR gene . . 2007-03-11 . dead . https://web.archive.org/web/20120209042027/http://www.szgene.org/meta.asp?geneID=4 . 2012-02-09.
3. Web site: Meta-analysis of all published AD association studies (case-control only) . . 2008-08-02 . dead . https://web.archive.org/web/20120225082211/http://www.alzgene.org/meta.asp?geneID=70&polyID=155 . 2012-02-25.
4. . The thermolabile variant of MTHFR is associated with depression in the British Women's Heart and Health Study and a meta-analysis . . 11 . 4 . 352–60 . April 2006 . 10.1038/sj.mp.4001790 . 16402130. free .
5. Schmidt, Rebecca J. . Hansen, Robin L. . Hartiala, Jaanad . Allayee, Hoomand . Schmidt, Linda C. . Tancredi, Daniel J. . Tassone, Florab . Hertz-Picciotto, Irvaa . Prenatal Vitamins, One-carbon Metabolism Gene Variants, and Risk for Autism . 2011 . . 22 . 4 . 476–485 . 10.1097/EDE.0b013e31821d0e30 . 21610500 . 3116691 . 2011-06-20.
6. . C677T and A1298C polymorphisms of the methylenetetrahydrofolate reductase gene: incidence and effect of combined genotypes on plasma fasting and post-methionine load homocysteine in vascular disease . . 47 . 4 . 661–666 . April 2001 . 10.1093/clinchem/47.4.661 . 11274015. free .