Survival and psychomotor development with early betaine treatment in patients with severe methylenetetrahydrofolate reductase deficiency
IMPORTANCE: The impact of betaine treatment on outcome in patients with severe methylenetetrahydrofolate reductase (MTHFR) deficiency is presently unclear. OBJECTIVE: To investigate the effect of betaine treatment on development and survival in patients with severe MTHFR deficiency. DATA SOURCES: MEDLINE, EMBASE, and Cochrane databases between January 1960 and December 2012. STUDY SELECTION: Studi