Coppedè F, Bosco P, Lorenzoni V, Denaro M, Anello G, Antonucci I, Barone C, Stuppia L, Romano C, Migliore L. The MTRR 66A>G polymorphism and maternal risk of birth of a child with Down syndrome in Caucasian women: a case–control study and a meta-analysis. Molecular Biology Reports. 2014 Jun 26;41(9):5571–83. doi: 10.1007/s11033-014-3462-5.