No effect of folic acid and methionine supplementation on D4Z4 methylation in patients with facioscapulohumeral muscular dystrophy

Facioscapulohumeral muscular dystrophy (FSHD) is associated with a contraction of the D4Z4 allele on chromosome 4qter. There is also marked DNA hypomethylation of the D4Z4 allele. The DNA hypomethylation may have a central role in the pathogenesis of FSHD. Supplemental folic acid can boost DNA methylation. We evaluated the effect of oral folic acid and methionine supplementation on the methylation level of 4qter D4Z4 alleles in peripheral-blood lymphocytes of nine patients affected with FSHD and six healthy controls. Methylation levels did not change, while recommended serum-folate concentrations were reached.