www.dearpharmacist.com/2013/08/08/2394/ A few snippets from the site(to avoid copyright issues):
"Methylation is the process of taking a single carbon and three hydrogens, known as a methyl group, and applying it to countless critical functions in your body such as: thinking, repairing DNA, turning on and off genes, fighting infections and getting rid of environmental toxins to name a few."
"Methylation also plays a role in making and breaking down various neurotransmitters, such as energy producing epinephrine and sleep producing melatonin. Most people are concerned about
making enough neurotransmitters but don’t sell yourself short. If there’s a problem breaking neurotransmitters down, then they will hang around in excess which may cause unwanted issues such as seizures, insomnia, panic attacks and fits of rage to name a few. See how methylation might apply to you or someone you love?!
Consider the people who might have a methylation problem: Children with autism, anyone with a seizure disorder, neurological condition, Alzheimer’s disease, cancer, severe Lyme disease, chronic infections, low T cells or reduced NK cells, diabetes, allergies, fertility issues, miscarriages, cardiovascular disease, chronic fatigue, anxiety or any psychiatric illness. Oh, and if you are extremely sensitive to medicine, or to laughing gas (given by the dentist) you might have a methylation problem, too."