evidence: MTHFR genetic testing: Controversy and clinical implications - PMID: 27052143 MTHFR genetic testing: Controversy and clinical implications [...] A Study of the MTHFR Gene Prevalence in a Rural Tennessee Opioid Use Disorder Treatment Center Population.Int J Environ Res Public Health. 2022 Mar 10;19(6):3255. doi: 10.3390/ijerph19063255. Int J Environ Res Public Health. 2022. PMID: 35328943 Free PMC article.