Methylation of erythrocyte membrane phospholipid in patients with early-onset myotonic dystrophy.

Methylation of erythrocyte membranes was compared in 10 patients with myotonic dystrophy (MyD) and sex- and age-matched healthy controls. The incorporation of 3H-methyl groups into phosphatidylcholine (PC) increased with age in the controls. In all 5 patients with early-onset MyD, 3H-methyl incorporation into PC was significantly higher than in sex- and age-matched controls. In contrast, 5 patients with adult form MyD showed incorporation rates into PC that were not significantly different from the controls. Our findings may confirm the presence of differences in the methylation of cellular membranes in MyD patients with the adult- and early-onset forms of the disease.